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Screened flexible cables (wires) - specifications & sources ...

06 May.,2024

Screened flexible cables (wires) - specifications & sources ...

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fabrica

This thread has been trimmed. The original is in the archive here:
http://www.mechmate.com/forums/showthread.php?t=505 (http://www.mechmate.com/forums/showthread.php?t=505)

Gerald,

How many wires go from the Gecko drive board to the steppers? Do all wires have to be screened including the power cables?

Gerald_D

We must be careful of the words here because we don't want any confusion....

There is a single cable from each gecko to each motor. That cable contains 4 wires (4 cores). Also, around the cores/wires is a single metal screen/shield. The screen/shield is not connected to the motor, but at the gecko end the screen/shield is connected to ground/earth point (the plate "under" the gecko). These cables can be about 11 meters [35 ft] long each and they need to be fairly flexible. We used 1.0mm2 Ölflex from Lapp

I am not sure what you mean by "power" cables?

fabrica

Thanks for your info Gerald, What price did you pay for a meter of the Lapp cable that you are using? the local guys are quoting around US $ 5.00 per meter for Pirelli brand.

One more thing Gerald, Did you find any specific part number for the Olflex cable that you are using?

Gerald_D

The full description for the stepper motor cable is "ÖLFLEX CLASSIC 115C 4 G 1.0mm sq" which cost me $1.65 per meter (50cents per foot)

fabrica

Thnaks Gerald for you effort. This stuff is not avilable localy. I will will have to import this from Singapore where they have stockists for LAPP.

Gerald_D

If you are doing a special import, then you need a complete list of all the cable types running to the gantries and cars - all these cables need to flex and all should be screened. (Your laser may also have special cable requirements)

This is what I have on the MechMate now:

4 cables, 4 core, 1.0mm2 for the 4 steppers
1 cable, 4 core, 1.5mm2 for the spindle main motor. (9 amp)
1 cable 4 core, 0.5mm2 for the spindle fan and thermistor
1 cable 7 core, 0.5mm2 for input/output signals from the breakout card (not all cores are used yet)
1 cable 4 core, 0.5mm2 for 220V power/control. (2 cores used for E-stop)

(I recall that I ordered 11 meters to the z-axis and a bit shorter to the back x-motor - my control box is high on a wall behind the walking area)

There is also a single green 6.0mm2 cable for ground/earth (not shielded). This you must have locally.

The price of copper went up internationally by about 50% last year - of course that is the excuse why cable prices have risen sometimes by 100%!

fabrica

Given below are the prices which I receved from my Singapore supplier(ex-works singapore) for LAPP cables. Hopefully this info would be of some benifit to the other guys on this forum.

1. 4 Core 1.00 mm2 [18 AWG] for steppers (Part No 1136204) SGD 2.70/mtr (US$0.53/ft)
2. 4 Core 1.5 mm2 [16 AWG] for spindle (Part No 1136304) SGD 3.60/mtr (US$0.71/ft)
3. 4 core 0.5 mm2 [21 AWG] for Fan/Thermister SGD (Part No 1136004) 1.95/mtr (US$0.39/ft)
4. 7 core 0.5 mm2 [21 AWG] for BOB control card (Part No 1126107) SGD 3.60/mtr (US$0.71/ft)

The above given prices are quoted in Singapore Dollars. (I added the US$'s - Gerald)

Gerald_D

Here is some info on those cables:

http://www.lappusa.com/Spec_Template.asp?nGroupID=10114

reza forushani

How many meters/feet of each cable do we need to order?

Gerald_D

See Doug Ford's summary later in this thread

reza forushani

. . . . . I am going to start with a router and see what happens. So should I use 2.0mm2 [14 AWG] for that since you mentioned thicker for router?

Gerald_D

When you use a router out on a construction site with a long cable, what gauge wire would you be using? I presume you are talking 110V and quite a lot of amps? The gauge (mm2) of the router cable for the MechMate will be the same as that. (Our cables in this country, or Europe, would be thinner because we are 220V)

Modified for a 115V router application: . . . . . . . . .

4 cables, 4 core, 1.0mm 2[18 AWG] for the 4 steppers
1 cable, 4>3 core, 1.5>(2.0)mm2 [14 AWG] for the spindle main>router motor. (15 amp?) 2-core if router has only a 2-core cord.
1 cable 4 core, 0.5mm2 [21 AWG] for the spindle fan and thermistor >
1 cable 7 core, 0.5mm2 [21 AWG] for input/output signals from the breakout card (not all cores are used yet)
1 cable 4 core, 0.5mm2 [21 AWG] for 220V power/control. (2 cores used for E-stop) (only 2 cores are needed, but you might not be able to get it)

Gerald_D

Apparently 14gauge or 2.0mm2 is right for a 15 Amp single phase router in 110V countries.

In 220V countries you can use 1.0mm2 for the big routers because they will draw around 8 Amps at the higher voltage.

Gerald_D

I have just counted the strands in some Lapp Ölflex Classic that are here at home:
1.5mm2 30 strands (16AWG)
0.5mm2 16 strands (21AWG)
Their spec, from the links above, says bend radius of 20x where there is movement and 6x for static. Maybe I went a bit overboard with my cables for this application? Cables are seldom discussed on all the CNC forums.

Gerald_D

I've just remembered how I actually found the economical cables.....phoned around an asked for the "simplest/cheapest braided screen cable that you have - not aluminium or Mylar foil - proper braid"

Håvard

Hi,

I feel a bit stupid to have jumped right in here. I did not realize that the cables get thinner when the AWG increases... Who came up with those units anyway? I'd like to tell them a little something.

Gerald_D

http://www.mechmate.com/Forum/messages/3347/15225.gif

Gerald D

My suggestion for the motors has always been 18 gage, mainly because it is a substantial, strong wire. You could go thinner. Quoting Mariss Freimanis on 29 Aug. '07:

"Most will agree 22-gage wire is pretty small (0.64mm or 0.025"
diameter). Let's see how it would work out wiring to a 7A per phase
motor 10' (3m) away.

22-gage wire has 0.16 Ohms resistance for a 10' length. Two wires are
needed per coil so that's 0.32 Ohms. The voltage drop will be 2.2V due
to wire resistance at 7A. If your power supply voltage was 65VDC then
it just became a 63VDC supply as far as the motor is concerned. Will
your motor know the difference? Not at all; it draws 7A at low speed
where supply voltage doesn't matter.

At high speed your motor phase current drops to 3A. The cable drop
becomes 1V, the supply becomes 64VDC instead of 65VDC. Does the motor
care? Not at all again.

Will the cable melt? Cable dissipation is 7^2 times 0.32 or 15 Watts.
That works out to about 1/8W per inch. It will be warm but not hot. At
high speed it's 3W and 0.024W / inch. Not even warm."

Doug_Ford

There were many posts on suppliers prior to this one below - those posts are in the archive:
http://www.mechmate.com/forums/showthread.php?t=505 (http://www.mechmate.com/forums/showthread.php?t=505)

Gerald,

I think I've found a reasonable deal on cable for us North American builders and I'd like to get your opinion on its quality. It has a braided shield and a 10X bend radius.

The salesman at Tannehill is named Dennis and was very helpful. I gave him the part numbers for the Olflex 115CY cable you said was good. He said they didn't have it but that Helukabel makes exact duplicates of the same stuff (type F-CY-JZ , flexible, Cu-screened, grey) and he'd get those prices for me. He called back later with the info below.

Here is the link to the cable on Helukabel's website.

http://www.helukabel.de/index.php?lang=en&func=2p&func=2p&parentid=PG16&uparentid=PG1607&masterid=16320

These are his prices:

1.0mm squared (18 AWG) 4 core - $1.44/foot
2.0mm sqd (14 AWG) 3 core - $2.42/foot
0.5mm sqd (21 AWG) 7 core - $1.55/foot
0.5mm sqd (21 AWG) 2 core - $.93/foot

For each type of cable, there is a $25 cutoff charge.

He said the prices he quoted me could be obtained by anyone who wanted it. If Gerald says this is good stuff and anyone else is interested, Dennis's contact info is:

Dennis Holtgrave
Lapp Tannehill, Inc.
8675 Eagle Creek Parkway
Savage, MN 55378
952-881-6700 ext 3614
952-881-0743 fax

dholtgrave@lapptannehill.com

PS. I left a civil voicemail for the sales manager at my local Carlton-Bates but he never called back.

Doug_Ford

Oh yeah. Thanks Mark. And GaryC, I'm looking for braided shield so I don't have weird problems popping up later when the foil wears out. Thanks for the referral anyway.

Gerald D

Those Helukabels look just right technically, but it is still expensive compared to other parts of the world. Your government may have a high import tax on foreign cable from Germany . . . .

Doug_Ford

Thanks Gerald. Yeah, I noticed they were expensive but the price seemed to be a bit lower than what other guys had been posting over the past few months. Oh well, we all have our challenges getting parts depending on where we live in the world. I guess the ideal fulltime job to have, if you are building a Mechmate, is an international airline pilot.:)

Doug_Ford

If anyone is planning to order cables soon, please wait. Within the next couple of weeks, I hope to finish routing the cables on my table and I'll try to give y'all a more accurate estimate of the lengths required. This stuff is pretty expensive so you don't want to waste any if you can help it.

Tonight, I almost ripped out the Y axis e-chain so I could reverse it. I thought I might be able to save 6-7 feet of the 2 core cable used in the e-stop circuit. Then I realized that if I reversed the e-chain, I would use more 4 core cable used to run the motors. Anyway, I think everyone will need to order more than 35 feet of the 2 core e-stop cable. Mine ended up short and if I don't splice on some extra, I'll have to mount the control box on my table like Hugo.

smreish

Good note Doug.
FYI
A great source for "cut as much as you need" is from Skycraft Surplus in Orlando, Florida. They have a website and do mail order. They stock many 4/6/7/9 core chainflex/olflex and others for cable chain use. It all starts in the .43/ft range and goes up.

Doug_Ford

Today, I added the cables to my machine which is built to cut 49 X 97 inch sheets of plywood. In order to calculate how long to cut the cables, I took alot of measurements. I figured new builders could use this information when placing their orders so that they don't order too much or too little.

My recommendation is that a new builder wait until he has the table, gantry and car built and the e-chain installed so he can take his own measurements. He should also thoroughly understand the E-stop, pause and resume circuits so that he can mentally walk through the process of routing the cable. It isn't complicated but it also isn't as simple as it may seem. I routed my E-stop circuit incorrectly and I wasted some wire that I now have to reorder.

**IMPORTANT**: The cable lengths I'm showing below are from the point where THE CABLES ENTER THE MACHINE. That is the point where the e-chain is anchored to the table. If you order your cables without adding the distance to the floor, across the floor to the wall and up the wall to your control box, YOUR CABLES WILL BE TOO SHORT. You must decide how far the control box will be from your MM and how high the box will be on the wall and add that to your order. Also, ensure that you include in your measurement the distance inside the box to the component to which you will connect the cable (relay, Gecko, Terminal, etc.).

- Stepper motor cables. Each motor is connected directly to its Gecko drive in the control box using a 4 core cable.

Z-axis motor - 18 feet 6 inches + distance to control box
Y-axis motor - 18 feet 8 inches + distance to control box
X-axis motor (front) - 16 feet 6 inches + distance to control box
X-axis motor (back) - 7 feet 6 inches + distance to control box

- Router motor cable. The router is connected to the relay in the control box. You only need one of these two core cables. Its length is 18 feet 6 inches + distance to control box

- E-stop circuits. There are two E-stop switches under each E-stop operator (or button). One switch is connected to a circuit that shuts off the contactor. You need a separate 2 core cable for this circuit. The other switch is connected to a circuit that uses the PMDX breakout board to perform the stop. The wires for that circuit are part of the seven core cable. The other wires in this cable are for the pause and resume circuits. Both the 2 core cable and the 7 core cables are the same length overall and may be routed along side each other.

Both the 2 core and 7 core cables will be divided into three pieces:

The first cable will be 7 feet 6 inches long + the distance to your control box. That cable will run from the control box through the X-Axis echain to the E-stop/Pause/Resume box mounted on the gantry on the backside of the MM.
The second cable will be 9 feet long and will run from the E-stop/Pause/Resume box mounted on the gantry on the backside of the MM through one of the gantry tubes to the E-stop/Pause/Resume box mounted on the gantry on the front side of the MM.
The third cable will be 11 feet long and will run from the E-stop/Pause/Resume box mounted on the gantry on the backside of the MM through the Y-axis echain to the E-stop/Pause/Resume box mounted on the car.Be sure you connect the E-stop switches in series.

Please make sure you give yourself some additional wire so that you have working room to strip and make connections to the switch terminals.

If you are building a machine that cuts larger sheets of plywood, you will need to change these lengths.

gmessler

Thanks for the info Doug. :)

Gerald D

That's very useful Doug! Thanks!

Doug_Ford

Gerald,

Please check my work. I could be wrong. Heck, I can't even wire up a contactor.:o

Gerald D

This is how a single cable is internally looped to get a series connection between switches:

598

That second pair of cables that Doug mentions for the e-stops . . . .
- from the button box on the "far" side of the gantry, furthest from "home" position
- to the button box on the "near" side of the gantry
. . . . . is static cable - it can be be stiff foil-screened cable - it is not required to flex.

Marc Shlaes

Doug, relax!

You have done a wonderful job on your machine in a very short time. If you were perfect, I don't think you would be working for a living.

:p:p

domino11

Doug,
I appreciate your posts, as I am in the process of getting my materials together, and as Gerald had mentioned, I read all the construction posts that I can and try and learn as much as I can from everyone! :) I save pictures, hints tips, and everything I can to help me in my build. Hopefully I will be posting my progress in the future and you will have the chance to see my mistakes :eek: and hopefully point me in the right direction as well. Thanks for your pictures and posts. :)

Gerald D

Right guys, you saw how Doug wrote a very useful summary, and you probably also saw a little editing to remove areas that could have caused confusion. My message is; don't be shy to write up your summary of a thread that has been rambling on too long and has taken too many side tracks - these summaries can be tuned and edited to make them 100%.

Greg J

Doug,

Thanks for the wire info. I'm getting close (before Christmas :)) to ordering the cables and "tracks". Should have pic's of table shortly (3 weeks ?) Just waiting on my rails.

Your posts and information are invaluable.

Doug_Ford

Greg J,

I strongly recommend that you measure things for yourself on your particular machine. Use a stiff rope in lieu of the cable. I might have made my e chain shorter than yours or I might have routed my cables differently from how you imagine. I sure would hate for you to come up short and it be my fault.

Greg J

Doug,

Good advice. Will do.

ekdenton

Having a hard time though finding the sheilded multicore wire here though. No one returns phone calls and most only sell to electrical supply companys or people who buy the 500ft rolls. :D

Doug_Ford

Ed,

I spent a long time trying to find a good deal on shielded cable and ran into the same things you did. If you'll look at my post in the cable thread, you'll find all the information you need to order from my source. Not a great deal compared to what Gerald can get in South Africa but it was the best I could find.

smreish

Go to skycraftsurplus.com. They are in Orlando, Florida and will sell you anything wire like (and just about anything else) for pennies. I bought all my shielded cable for around .27 or .32 cents/ft....any length.
They also have a nice selection of Nuetrik XLR's too.
Sean

sailfl

I will second on the prices of cable. Though I am not building yet, I have checked on the prices and they are going to be close to the numbers that Sean quotes.

J.R. Hatcher

My machine took near 200' of 4 conductor wire. I will admit I wasted a little on each run (didn't want to cut it short).

Greg J

I bought my wire from Doug's source. Good service, allways returned calls/emails, etc. Took 3-1/2 weeks to get.

smreish

...and because I built a 5 x 10 table, I used 275' of cable.

ekdenton

Here is another source on the Helukabel cable.

http://www.hitechcontrols.com/cable_index.htm

They order once a week and have a three week turnaround. I spoke to Jim at hitech and explained what I would be using the cable for and he suggested that if a UL label was not necessary then it would be cheaper to use the following type cable.

Gerald D

Ed, it would appear that these cables have a bigger outside diameter - ie. they are "bulkier" and therefore stiffer. Keep an eye on your cable chain radius and the minimum bending radius allowed for the cable.

ekdenton

Thanks Gerald, The pvc coated cable does have a smaller diameter and a smaller bend radius. I will see what he has in the pvc.

Gerald D

Ed, if the difference in price is significant, I would probably use the cheaper, thicker one.....even if it bends a little tighter than spec'ed. In our router application we a putting relatively few bends per minute onto that cable.

Doug_Ford

I love the fact that the cores are different colors. The cable I used had all black cores with tiny numbers written on them. It was a challenge to read them sometimes. These would be much easier to use.

Roadkill_321

I have found that prices can vary widely depending where you are from. I had a company up here in Canada, actually in Saskatoon, SK quote me a price of $1500.00 for 263 feet of Olflex 115CY cable.

I checked with another U.S. based source for the Helukable wire which as far as I know has only minor differences with the Olflex, and they quoted me about $500.00 for the same length.

I can't explain it, but price gouging come to mind.

John

ekdenton

Hey Doug, do you have the heukabel part #'s that you used on your cable that you have the prices listed for? I just got an email with prices:eek::eek:
Jim must be pricing something altogether different. The non sheilded prices were about what you have shown. Here is the email:

Ed,
Listed as follows are your pricing for the shielded products that parallel the previous quote.

PN-89960 JZ 602 RC-CY 200 ft. $4.00/ ft.+$25.00 cut charge (200 ft.)
PN-89978 JZ 602 RC-CY 40 ft. $4.33/ ft.+$25.00 cut charge or rest length @ 15mtr.(49 ft.)
PN-49643 SUPERTRONIC-C-PVC 50 ft. $1.41/ ft.+$25.00 cut charge or rest length @ 24mtr. (79 ft,)
PN-49646 SUPERTRONIC-C-PVC 100 ft. $1.59/ ft.+$25.00 cut charge or rest length @ 29mtr. (95 ft.)

Best Regards,

Jim Shiels

Inside Technical Sales

Hi-Tech Controls

14853 E. Hindsdale Ave. Suite D

Centennial, CO 80112 USA

Phone: 303-680-5159 / 800-677-8942

Fax: 303-680-5344

Doug_Ford

Ed,

I'll try to find them for you. I hunted around for quite a while and I don't think you can beat the prices I got for the small quantities we need. Not in the US anyway.

ekdenton

Okay I found out some more usefull info.

The Helukebel JZ-HF-CY application shows to be for robotics and cable trays. I checked with Dennis Holtgrave at Lappusa and also Jim at Hitech controls. Lappusa was a few pennies less for the 7core but Hitech was less on the 4core 18AWG which I will be needing the most of.

listed earlier in this thread, The Helukebel F-CY-JZ cable application is more twards computer cables and doesn't mention robotics or flexibility(other than bend radius) in the pdf sheet. It does cost about .50 per ft less, but IMHO doesn't sound like the correct cable for what we are building.

I ordered the JZ-HF-CY type cable from hi-tech.

The JZ-602-RC-CY rubber coated 4core 18AGW Helukebel was out of my price range at $4 per ft.

ekdenton

Gerald D

I would be perfectly happy with the F-CY-JZ cable for our low-speed application.

liaoh75

I am in the process of acquiring parts and ran into some wire issues. I've read the information on this thread from beginning to end several times and I've looked around for "flex" wire with braided shield. There is wire sold here that has both braided and foil shield that is substantially cheaper than import Olflex that is recommended. The only problem is – it’s not advertised as "Flex" wire. If I go with the "Flex" wire, it will cost me about 3X more. My question is can I get away with using this wire instead of "Flex" wire? I'll try to get some pictures of this stuff and post it so you can see what I'm talking about in a day or two when I get a sample of this stuff. The price is $1.60 per meter for 4 core 2.0mm stranded wire (Sorry, only metric specs available here in Taiwan). I would imagine the 1.0 mm per core would be cheaper. Has anyone tried wire that is not officially labeled as "flex" cable for robotics/chain application? I'll still post pictures of the stuff I'm talking about but any suggestions or words of wisdom would be appreciated. Thanks.

smreish

I am using a "flexible" but not official flex on my machine. I haven't noticed any issues like cracking or otherwise. I did use an 18ga with a very light PVC jacket that has both the braid and foil. Cheap. .40 / ft. For now, everything working fine after 5 months of hard use.

Gerald D

David, the "flexibility" will mainly be decided by the outside diameter and fine coppercstrands inside. We don't need a lot of wall thickness to protect the cable because we enclose the moving cables in chain. Any thin wall cable with fine strands can be considered flexible enough for our application, which actually is a low grade application by "CNC tool" standards. We are not spitting out 200 widgets per minute.

Lots of people have used unscreened cables and they swear by them. However, when interference problems arise, the first suspect is the cable. Consider that the sheer size of the MechMate makes for very long cables, running closely parallel to each other. The guys going problem-free are mostly hobbyists with smallish tables.

If I was on an absolutely tight budget, I might go for unscreened motor cables, but definitely do good screens on the control circuit.

liaoh75

Thank you Sean and Gerald for the reply. I will post a picture of this stuff tomorrow but it has a black pvc shield that is about 1.2 mm thick. I think the next logical question would be, if there is interference, and assuming it does not originate in the carefully shielded control box, what kind of indicators would one expect to see? Would it be missed steps, eratic motor jerks, etc...?

Gerald D

Yes, missed steps and erratic movement.

The most common complaint seems to be a z-slide that decides to dive into the table, and I suppose that gets the most complaints because it is so dramatic! :)

J.R. Hatcher

I have had that happen several times :o. I never knew I could have blamed it on machine error ;). Just joking, mine was 100% operator error ..... but if Gerald had spoke up a little earlier :rolleyes:.

Gerald D

:p <-----sticks out tongue

J.R. Hatcher

William McGuire

Curious...
Does this wire have any identifying names, numbers or marks?

J.R. Hatcher

Bill this is the writings on all the wires, it is exactly the same, no variance regardless of wire color. The pictures overlap just a little. All 3 pics are 1 wire.
I did cut up a small piece and 26 small wires make up 1 conductor. I have e-mailed the guy to see if he has gotten any more of this wire.

William McGuire

I found this company (Northwire) and site for the wire...
http://northwire.com/directFFSpecs.php

I haven't checked their price or availability yet...

Robert M

Hi guys,
What is your opinion on “IGUS chainflex” wires & cables ?
I’d appreciate some feedback & comments!
Robert.

Gerald D

http://www.igus.com/chainflex.asp

Obviously they are professional cables - but are the prices right for you?

domino11

IGUS,
make some of the most flexible cables in the world. They quoted on a military job I was doing some engineering work for about 7 years ago. The cable we needed was rather large and needed a small bend radius. They designed a cable that met the criteria flawlessly. Too bad the price was 4 times that of everyone else. :eek: If the budget allows, they will be good cables. :)

liaoh75

Hi Again, Sorry about the delay in posting the picture of the wire. I got tied up over the last several days entertaining family from back home. There are 37 strands per core. Can you guys let me know if this looks ok? The shield is copper but not as tightly woven as the one J.R. Hatcher posted. Any comments or suggestions are welcomed.

Thank you
1737

Gerald D

That looks good - I don't see any problem with it

Alan_c

Gerald, what was the size (gauge) of the cores for the cable between the control box and the VFD (7 core for control signals), I am assuming 0.5 would suffice or would 1.0 be better?

Gerald D

1.0mm2 will be no better than 0.5mm2 for the VFD control signals.

woodfish510

I'm using what sounds like the same wire (bought it off eBay). I liked it so much I bought some more a 2nd time and then went back a 3rd time and bought all the guy had, enough for about 4 machines (Marc, Gene and another for myself). This is very high quality wire. It's has a braided shield, a Mylar foil shield, and a drain wire. It's 18 awg, 4 conductors (1 of the red ones is 6 conductors), each conductor has about 25 very fine wires making it extremely flexible. I have not had any issues with this wire at all.

You didn't get it all, because I just got 300 feet from him. And like you I think the wire is great and not expensive. He sent me a small section of wire before I bought it. He has fast shipping as well. It has a small bending radias and should work fine.

domino11

JR,
I noticed from some of your pics that your wire is rated for only 30V. Will that be a problem for your motor drives (are you using higher than 30V for your motors?) ? Or maybe just using it for your limit switch stuff?

J.R. Hatcher

Heath I saw that too and figured it wasn't actually the volts the wire can carry because of it's size (20 awg, I posted it as 18 ga. but was told by the supplier that it is really 20 ga.). Think about how small a auto spark plug wire is and it carries something like 10,000 - 20,000 + volts and it's not really wire, years ago they were graphite, not sure nowadays. Besides if it is talking about volts I think it's some kind of weird specification that doesn't apply here. I'm running mine @ 70 volts and it's doing fine. When I connected it to the motors I noticed my wire was much larger (theirs looks to be around 24ga. or even smaller). But thanks for the watchful eye anyway.

PS

Copied this from a website for 20 ga. wire: notice the lowest UL rating (600 volts) compared to the CSA rating (150 volts).

Voltage Rating

MIL-W-16878E Type B: 600 Volt UL 3265, CSA AWM I A/B FT1: 150 Volt
MIL-W-16878E Type C: 1000 Volt UL 3266, CSA CL 1252 XLPE: 300 Volt
MIL-W-16878E Type D: 3000 Volt UL 3271, CSA CL 1251 XLPE: 600 VoltSpecifications

CSA AWM I A/B FT1
CSA CL 1251 XLPE
CSA CL 1252 XLPE
CSA: 125C, 150, 300, 600 VOLT
MIL-W-16878E Types B, C and D
MIL-W-16878E: 105C, 600, 1000, 3000 VOLT
RoHS Compliant
UL
UL AWM Style 3265
UL AWM Style 3266
UL AWM Style 3271Product Description

Conductor: Stranded Tinned Copper
Insulation : Radiation Crosslinked Polyolefin (XLPE)

Gerald D

I saw that 36V on the cable, but didn't think it meant the voltage limit on the cable's insulation. I can't believe that any cable would have such a low voltage rating.

JR, the voltage rating of the cable has nothing to do with the copper content. It is an indicator of the quality (and thickness) of the insulation.

domino11

JR,
I was not worried about the size of the wire , but rather the insulation covering the wire. You can easily pass thousands of volts through a very small wire, the insulation doesnt stop you from doing this, but it does keep it from arcing and shorting to adjacent wires and metal. The wire size limits the amount of current you can pass without the wire melting. If the insulation on the wire is not capable of supporting the voltage you are passing on it, at some time, the insulation will break down and you will have a short circuit. 30V wire will probably not show a problem right away, but might be a time bomb waiting to go off after some use and aging. There was a picture of a chap on the shopbot forum that almost had his garage burn down due to an electrical problem with his cnc. Just wouldnt want it to happen to one of us.

orotemo

Regarding the pause and resume:

Why seven core (mentioned on page one of this discussion) cable for the pause/resume/E-stop ? if I get it right, a MM builder will only need the 5V, GND E-stop, pause, resume, counting 5 distinct cores.

Right or wrong?

Gerald D

Probe? z-zero plate? Any other device?

Always a good idea to have some spare signal wires already in the screen.

smreish

...laser power, LED lighting...the list goes on.
Actually, I now wish I used that 9 core I had sitting on the shelf!

Gerald D

Our Ölflex "classic" cable is available in 2/3/4/5/7/12 cores. This is my thinking for the gantry cabling where a spindle is used. Doesn't show the obvious motors and spindle power cable:

1772

Note the enlarged button box for the 5 cable entries on the left.

If proximity switches are used, the 12V supply will be on the 7-core cable.

orotemo

I will probably change my order to a 12 core cable then. Thanks a lot guys. I'm a quick learner (when people explain to me realllllyy slowwww :)).

Gerald D

Keep an eye on the outside diameter of the cable - if it gets too thick it will not like to flex inside the cable carrier.

Gerald D

After a lot of consideration, I have decided to reduce wire gauge (go thinner) for our stepper motor wires. Originally we used 1.0mm2 (18gauge), which was a match to the Gecko's capability of 7 Amp and when we toyed with going to bigger motors in the longer term, which included the possibility of paralleling the coils in some motors.

Since then we have moved away from big, high-current configurations and I cannot realistically see our personal situation going over 3 Amps. Mariss has also written some interesting comments on why stepper motor cables can be really thin. (See post of 08 September 2007 in this thread)

So, we will be ordering 172 meters [564 ft] of 4 core 0.5mm2 [21 gauge] screened cable tomorrow. (R13.92/meter [$0.57/ft]) Ölflex Classic 115CY 4 G 0.5

Alan_c

I was wondering why I was taking so long to make up my mind on the final order of my cables, this must be it :).

Do you think I will be safe to use the same for my 4.5amp (PK299's) motors or is that pushing the envelope a bit much?

Is that price excluding VAT?

ps: could you give us a breakdown of the cable lengths you are using for each run, all the other lengths on this thread are for "small" 8'x4' machines, I just want to check them against my estimates to make sure I am not buying too much and wasting cash. It might be of benefit to the other SA guys building to our bigger size.

hennie

Alan what lengths cable chains did you get from RS? I need to order mine also.

Gerald D

I think it is technically okay for the 4.5Amp motors. See the post by Mariss referenced above. We shouldn't see warm cables, even when a couple of them are bundled together. My biggest concern on reducing the size is their strength where they enter connecters and terminals, but I think that I have learnt to be careful in that department.

Here is the "calculator" for the lengths. Some of the allowances on the y-car seem far too generous, but we have verified them by actual measurement . . . .

Alan_c

Gerald

Thanks for the calculator, it mostly confirms my estimates.

I see you have changed to a 5 core cable for the "power" to the junction box on the y-car, why the extra core (2 for fan, 2 for thermistor)?

ps: the pdf file in the above zip only shows half the junctionbuttonboxes drawing, B end of gantry is cut off. fixed

Alan_c

Gerald, another question

Cell E14 gives the length of the 220V E-stop (2 core) cable from the 2PB to the Y-car, what about the length of cable from the control box to the 2PB box, how does the signal get back to the box. This may tie up with my query above but surely you need two wires to carry the signal back to the contactor?

Gerald D

I see you have changed to a 5 core cable for the "power" to the junction box on the y-car, why the extra core (2 for fan, 2 for thermistor)

It is also the junction for the mains E-Stop.

Gerald D

Puts the little fan on the wrong side of the e-stop contactor, but still on the right side of the isolator . .

1783

Plus 2 more cores for the thermistor

Alan_c

:o OK got it worked out, not too bright this morning.

Gerald D

A 1 amp mains supply to the y-car may have more uses . . . .

lumberjack_jeff

I just got an email from Vladimir of Skycraft Parts and Surplus http://www.skycraftsurplus.com

He has Belden 7402A wire available for $0.162/foot. Mouser (http://www.mouser.com/catalog/630/867.pdf) sells it for $160 for a 250' spool.

Unfortunately, I already bought my wire, and paid quite a bit more for probably inferior wire.

Gerald D

But that is un-shielded wire?

Gerald D

7402AS is shielded

http://www.belden.com/pdfs/03Belden_Master_Catalog/18Industrial_Cables/18.31_40.pdf

paul60

After reading this post i had a look at my shopbot prt97 stepper motors
cables. None has any screening on them.
not sure if the later shopbots are screened.
i was hoping to hook my Mach3 control board to my existing cables
but if there is the possibility of problems i will have to order new cables.
or run with existing cables for testing then import correct cables.
any feedback would be a appreciated.
paul

domino11

Paul,
As far as noise goes, I would aways prefer a shielded cable over a non shielded. The control signals are the ones that really need attention, anything that is low voltage control signals (estop etc). I would suggest making sure those are screened at the minimum. The motor cables wont care about noise themselves but a shielded cable there will help them not to radiate noise out to other things. So you could do it in steps if you wanted.

sailfl

Paul,

From my little experience, I would agree with Heath. Shielded is better.

Gerald D

Use your existing motor cables for a start. Your e-stop is the one that most needs a shielded/screened cable. Or keep the e-stop cable far away from the motor cables.

If all your cables are screened/shielded, then you can stop worrying about keeping a distance apart.

paul60

Thanks for your replies, very helpful. will go with what i have and replace with
screened cables once i have everything going
paul

Robert M

Gerald,
In the essence of keeping cost down but no sacrifice to risking trouble, how important is it to have screen cable for a router source.
Can a regular 14/2 for a router attract some possible trouble ?
Not a big deal, +/- 120 us $ for a 14/4 new shielded cable ( I say 14/4 cause 14/2 or 14/3 difficult to find ! ), but if not necessary, then....why ! !
Thanks, Robert

bradm

Time for me to air some dirty laundry:

My motor wires are screened. My estop circuit wire is screened.

My proxy sensor circuits and z-zero circuit are not screened, although they are run as twisted pairs; the whole set is in one cat-5e ethernet cable. My router power was not screened, and my spindle power is not screened.

I'm not 100% comfortable not screening the spindle power lines, but I had the wire lying around and I wanted to get the spindle up and running. If anything goes unreliable, it's the first thing I'll replace during debugging.

In my thinking about this, the motor cables are a potential strong noise transmitter; they are high power lines at high and varying frequencies.

The router power was relatively insignificant; it's high power, but at a consistent frequency, and there's plenty of other unshielded lines of that ilk all over my shop.

The spindle power is a likely the strongest transmitter in the shop, but thus far no issues.

The proxy switches are not a transmitter, but might be a receiver of noise. However, the consequences of a noise problem are minor from a safety perspective, and they are very basic on/off signals.

The E-stop is in it's own shielded wire, because, well, it's the E-stop.

So, I think you're okay not screening the power to a router, especially if it's just on/off. If you are using a speed control external to the router, then you might be more careful. Of course, if anything goes weird, the first thing to do is switch to a shielded cable.

Gerald D

The routers have brushes and the brushes wear out. Have seen too many reports of folk that cure their noise problems by running the router cable straight up to the ceiling and far away from the other cables. The router cable is high on my list for getting a shielded cable.

bradm

Good point. Dirty commutators and brushes sparking would be a substantial noise source. Missed that one.

fredjr

I need some opinions on this cable that I came across.This is the numbers and wording on the cable. "THE SIEMOM COMPANY SYSTEM 7 E116394 4 PAIR 22AWG SOLID CMP 75C (UL) C (UL) S/STP 2005 1102. There is a description of the wires. green/gray pair,pink-gray pair, brown/gray pair,gray/lite gray pair with a foil wrap around each pair. There is a small(.019")bare wire in the cable. I have the shield wire pulled back over the blue jacket.

http://i671.photobucket.com/albums/vv80/fredjr45/DadsParts135.jpg

http://i671.photobucket.com/albums/vv80/fredjr45/DadsParts137.jpg

inventall

The second most important thing about the wire in my opinion is that it is stranded not solid. The more strands in the wire the more times it can bend without braking. The armored shielding on the wires is not that important, if the wires are not rubbing on anything (e.g. run in cable chains). That is my opinion.
Also 22awg is very thin I believe that most are using 14 to 18 gauge for the motors. Sensor and input wires can be quite small.

lumberjack_jeff

My MM uses 22 ga wire approximately 30' long. After an hour of heavy use, the jackets on the wires are about 10-15° f above ambient.

I have a 57v power supply, and my steppers get much warmer than that... call it 130° f.

domino11

Jimmy,
The solid wire will not be very flexible and could break over repeated bending. Foil shield is good but foil and braid is better. I would probably opt for stranded wire.

kanankeban

bradm

Hector, the gauge (size of the conductors) affects the current handling capacity of a wire. The voltage that can be safely handled is a function of the insulation wrapping the wire. Most modern wire insulation is well up to handling any voltage you are likely to use, however, if the voltage is potentially dangerous, you'll also want to be sure that there is a low likelihood of physical damage to the insulation that could expose the voltage. So 20 AWG is just fine for your e-stop, as long as your e-stop circuit doesn't involve more than about 5 amps worth of current, and you a comfortable that the insulation won't get beaten up. See http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

cncb

Looking to rip out my cheap "security" cable as its not going to be the best long term cable for a cnc router. Has worked without failing but I don't want it to be running if it does fail. Really interested in this continuous flex control cable a few of you including Gerald have mentioned and or used on your mechmates. Wondered where any of you in the US have purchased this cable (either Lapp OLFlex classic or Igus Chainflex) and if you recall off hand how much you were paying per foot. I contacted Lapp USA and the rep tried to talk me into a more expensive more over the top robotic cable :rolleyes: that was around $7 a foot. I'm sure its good but I don't plan on ever running these cables nearly as much as they are rated for nor do I need the ratings/specs they carry.

Thanks in advance for any info.

jhiggins7

For more information, please visit FSW.

Brian,

I and others purchased our cable from this Ebay Store (http://stores.shop.ebay.com/jcoenterprises). I purchased 200 feet of 7 core, 20 gauge, stranded copper, shielded cable from him. I don't see it in his Ebay store at the moment, but send him a "question" using his Ebay store to check price and availability.

He was very helpful to me and has good service. He responds to questions, so be sure to ask. For instance, his store didn't say whether the wire was copper and stranded. I ask him, he repsonded, and it was. The delivered product was exactly what he told me it would be.

cncb

Thanks for the info I will contact that seller. Was hoping for a true distributor but ebay always works. From what I can tell Igus has more affordable continuous flex cable, but I'm still interested in Lapp's. Can I ask why 7 core? Aren't your motors 8 wire/4wire in parallel?

jhiggins7

Brian,

You are correct, my mistake, the wire for the motors was 4 core.

The 7 core is for the E-stops, etc.

As I recall, (my MechMate is not my current location), I ended up using two 4 core cables instead of one 7 core cable for my E-stops, etc. I appologize for not being more careful in my reply.

cncb

No need to apologize ;) appreciate any info you provide. Got Igus's catalogs today and will request samples tomorrow, Lapp has still yet to send me a catalog after requesting twice. Igus was prompt and so professional. Making me lean more and more towards Igus's chainflex. Always loved their cable carriers.

paul60

Found this information on ebay might be of interest to others
woodguy
http://cgi.ebay.com/CNC-Stepper-Motor-Hook-UP-WIRE-18-4-Buy-10-increments_W0QQitemZ260393170662QQcmdZViewItemQQpt ZLH_DefaultDomain_0?hash=item3ca0a476e6

cncb

That's pretty cheap but I think you get what you pay for. No brand name on it but is his description true? That stepper motors def. do not need to run with shielded cable? I'm sure it would take an awful lot to get a response from a stray signal to foul them up but I would rather not take my chances and just keep it shielded. Also 7 strands per conductor? I think some of the other flexible cable mentioned in this thread is around 25-30 strands per conductor? Wonder how flexible that cable really is. :o

domino11

Woodguy,
That wire is an unshielded wire. Its better to use shielded wire throughout the system to control noise. You also want the shielding on the stepper cables to keep the noise on them IN. :)

Robert M

Hi all,

To those who would be interested or are wondering which wireing to go if you should / want to use IGUS Chainflex (http://www.igus.com/igus/cflex2_i.asp?series=CF6&part=CF6-05-07)screen cable, here’s a few part # that I ordered for the beast !

- Motors, No: CF6-07-04 ( 4 conductors x 07mm (18awg))
- Data, No : CF6-05-07 ( 7 conductors x 05mm (20awg))
- Data, No : CF6-05-09 (9 conductors x 05mm (20awg))
-Roter/spindle : CF31-25-04 ( 4 conductors x 2.0mm (14awg))

Decided to go with IGUS for some few basic reasons:
First, in my case (in Canada) LAPP has no corporate warehouse, no distributor for the wire needed which means it had to be brought in from a office agent who in turns get’s it from USA main warehouse, which again meat I had to pay an astronomical price ( +/- 20-25%...freight, customs, duty…etc, more than what IGUS cost me at my door steps) but …the focal point aside prices, the LAPP agent knew basically zippo about some very basic tech info I was hoping to get and I had to run after him to get 1st a quote…. and that goes with he never returned my calls about turnaround time on an order nor a bitch attitude over the phone !?

IGUS, well, it was a fun experience.
1st, they have a local corporate rep that came the very next day I 1st called with some catalogs in hand !!
Call on the guy afterwards and get knowledgeable tech info, prices and anything else you can think of, related to what they offer and get answered with a friendly attitude on the fly anytime of the day. Just can’t say that nor could not find anyone for BELDEN and LAPP…well as said, rather eat sand than call on those arrogant bitches again !

So, as I can understand in some other countries, IGUS can be more money, but for me, cost less and get service & courteous answers…. Even if sometimes it can cost more, it is worth a little more $$....best of all, here in Canada it cost 2 to 3 time less than LAPP !!!

Mike O.

My Mechmate obsession has led me to scourer the internet, local stores, papers, dumpsters, and drainage ditches for shielded, braided, four conductor wire that would not break the bank but would ensure a successful Mechmate. I have even considered starting a new company to manufacture this product at a reasonable price, given the totally absurd prices I have received from several vendors, when I found this in the Mouser catalog http://www.mouser.com/ProductDetail/Alpha-Wire/86304CY-SL002/?qs=sGAEpiMZZMuPnr6I6Psi5eeALYFRXsnyvMCWtLf%2fdKc% 3d . It does not have a braid but it is shielded and is specifically designed for our application. It has been tested to 14,000,000 cycles which means it would probably last around 39 years in my little shop (1000 cycles per day). It’s 22 awg, a bit thin, but as Gerald has argued should be perfectly fine, it has a jacket diameter of .231 inches and bend radius of 8x its diameter for both static and dynamic use. Here’s a link to the Alpha Wire web page which better describes the product http://www.alphawire.com/Products/Cable/Xtra-Guard-Performance-Cable/Xtra-Guard-Flex/86304CY.aspx . Press the properties tab for specifics. At around .70 per foot that’s a bargain in the US for a viable solution. I know that many of you insist on the braid for fear of the foil alternative, wearing during use, but with a fourteen million cycle rating and at dramatically lower cost I’m inclined to try it. I’d appreciate your opinions before I lay down the $350 for a 500 foot roll.

cncb

I'm getting samples next week from IGUS for their chainflex, and at $1.10 a foot, no minimum order or cut charge I can't complain. Beats buying a whole spool and its made specifically for our use.

Mike O.

Brian, I'm planning a 14' table, which will require about 400' of cable. If I order 500' at 350 dollars that will be 90 dollars less than the igus and give me a hundred feet of spare. Additionally, the alpha wire is specifically made for continuious motion, robotic and extreme high flex use. I am however interested in what you decide to go with and why. Are you sold on the braid, the availibilty of larger 20 or 18 guage or is it the igus name? Let me know, after you receive the samples, which specific cable you choose.
Thanks:):)

cncb

I understand, you need quite a bit. I'm sure you could get a better price on a spool though with Igus. Will keep posted which I go with but I'm almost certain it will be the chainflex from Igus. They had me sold on availability, prompt response and support, pricing and the quality of the cables they produce. Never used their cables before, just the carriers so I'm anxious to see the samples of the exact cable I want to use.

Mike O.

Brian, Thanks for your responses... Did you talk with igus directly or one of their distributors? Can you supply me with a specific Igus product number? I'd like to call them and see what kind of pricing I can get. Do you have a phone number or an individual you think I should speak with? Thanks again...

cncb

Mike,

I spoke with the local sales rep for my area which is the best person to speak with, check out their map on their site and see who your local rep is and call them directly. Inquire about pricing and samples if you want to play with the cable in hand, tell them your application and get any feedback you can. I've inquired about the CF140, and the CF140US, one having euro certification and one having us. Its a 4c 18ga shielded/braided cable.

Mike O.

Brian, Thanks for the information. I spoke with a gentleman at Igus today, and it looks like I might have to call your local rep because the prices quoted to me are much higher. For less than five hundred feet of the 4 conductor, shielded, 20 gauge chainflex I was quoted $1.87 per foot, for five hundred feet the price is $1.72 per foot. Often, manufacturers will not under cut their distributors and that may be what’s going on here. I had them quote the 20 awg. thinking it would be less expensive but in retrospect this may not be true if they manufacture more of the 18 awg. Bob at Igus is sending me a sample and was very helpful so I’ll give them serious consideration but at 2.7 times the cost of the alpha wire mentioned above its not likely. Thanks for your help.

cncb

Np, never hurts to shop around! Here is a copy and paste from the local sales rep for an official RFQ I received. With Igus there is no minimum order quantity and up to 10 cuts free of the same cable.

Pos Part Quantity UOM Price $ $ Total
1 CF140-07-04 1.00 $/Ft $1.15

They post current pricing on their site online too. Maybe he misquoted you? Was it indeed CF140 because CF140 is the cheapest of its class, they go up fast in price accordingly. But get the sample and play with it, the braided screen is so strong, without a relief cut along the cable to peel back the jacket you cannot pull it off it is so strong and the cable itself is super flexible. I like the conductor coding system too, having all black conductor insulation and just number coding each conductor.

Note: I had missed the note on their spec sheets prior to requesting the sample in regards to a ground/bonding/pe wire being included in the conductor counts. So a 4c18ga is really 3 conductors numbered and 1 yellow/green striped ground. Debating whether or not to just go with 4C and tube that conductor black as well (since not using a ground for 4 wire stepper motors) or to order a 5C18ga and snip the ground back and do it proper.

Gerald D

Guys, please guard against repeating quotations out here on a public forum, because this sometimes results in the big corporate clamping down on distributors who sell cheap.

cncb

Sorry Gerald. I tried to remove it. Btw this is not a quote from a distributor this is from corporate, IGUS sells directly.

Gerald D

Brian, the above stuff is not serious enough to start deleting yet - I just wanted to put a general note to everyone to be careful with comparing prices in public.

cncb

Gerald,

I understand your concern, will be a bit more careful with it.

Mike O.

Gerald, Sorry - I'll keep all mention of prices to private email. My apologies to Brian also, it seems when I misbehave I insist on dragging good people with me.

cncb

:D no worries we are all friends here. All I will say though is I'm thoroughly impressed with Igus's service and products. Can't wait to order a spool of this stuff.

smreish

I will say I have had impeccable customer service from Igus in the past. Good to hear. They also have a great website that allows you to download all other their products in 2d and 3d dxf drawing files. Very helpful.
Sean

javeria

Hi all - i recently had a cable (same on my Mechmate) put on a machine which I help to revive (victor cnc) some folks might have seen it on the cnczone -

now what has happened is that the cable has started to give up - shorts and cuts and all that.

I know that the small radius has caused this - so when I asked lapp to give me a suitable cable they guided me towards FD series (http://www.lappgroup.com/1/de/catalogue/catalog/power_and_control_cables/power_chain_applications/harsh_use_conditions/oelflexR_fd_classic_810_p/index.html) - wow! that cable unscreened is like 7.5USD per meter.

the question is for short radius - do i need to get that sort of cable - or there are suitable quality substitutes - ??

Gerald D

Irfan, the cable chain and the cables must be compatible - you need to find a balance between the radius of the cable chain/carrier and the bend radius of the cable itself. I think your problem is caused by the small radius of your chain?

Sherman McCoy

Just got a quote from a Lapp distributer in the USA for 2 cables:
4 Core 1.00 mm2 [18 AWG] 100' P/N 1136204 $ 5.02/ft
7 core 0.5 mm2 [21 AWG]100' P/N 1136107 $ 7.34/ft

Ouch! I should have known when the guy called in response to my e-mail, and took a day to work up a quote, that I was going to get bent. Oh yeah, 8 week delivery time.

Also seeing 25' lengths of 18/4cy NuFlex 1000 Shielded Flexible Control Cable(http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260507907955&ssPageName=STRK:MEWAX:IT) for $1.84/ft on E-Bay.

Not familiar with the brand, but the price seems reasonable. A lot of dealers on E-Bay seem to want to sell 1000ft spools. Most of the items that look like they might work are off-brand. Does brand matter? The Skycraft Surplus store seems to only have coaxial cable. I did notice that Quest uses shielded 21/7 when they install phone lines. I cut off a piece from a spool I buried, and although its not very flexible, it is well shielded. It's got to be cheaper than $5/ft.

paul60

a link to a shielded cable supplier.
http://www.action-electronics.com/wirecable.htm
http://www.cnccookbook.com/CCCNCNoise.html

jestah

Hi guys,

Just got off the phone to the NZ rep for lapp cables and he told me that using the 115c cable would not be wise in drag chain as over time the conductors would brake. Has any one found this with the cable they have been using and if now how much time has your cable been flexing for?

thanks
jestah

KenC

I don't think you MUST use Lapp cable, you would probly have a better chance walking into any electrical/electronics hardware shop & ask for "CY cable", you need 18 AWG (or 1mm2)4-core CY cable.

Gerald D

Jestah, that rep for the cable was just feeding you salestalk. Any cable can be used in a drag chain - it depends on radius of bend and number of cycles. Some hi-tech machinery out there move fast and through tight corners, while our MechMate is a plodder by comparison.

sailfl

Those that need cable.

I will go to Skycraft and talk with them about seeing if they can find a source of the cable that Josh just bought. It is 4 wire foil shielded at a price of $0.30 a foot. The also have 7 wire foil shielded for $0.35 a foot. This is the kind of wire that Sean and I have used and I believe a couple other builders have used. It may take them some time to find it. As they like to remind me when I am looking for stuff, they are a surplus store.

I will get back with you.

smreish

Nils,
Double check, I think 18/4 with foil also had the braided shield as well. I seem to remember extending that braided shield via soldered jumper!

"how's the mailbox? My truck misses it! LOL

swatkins

sailfl

I will make it a point to visit today and see what they have left and what they can do to buy more. Yesterday was not a good day for a visit.

sailfl

Steve,

You need to determine how much wire you want. The amount varies based on the location of the controller box to the table. You want to have no breaks between the motor connector and the controller box.

So you need the length for the motors, proximity sensors and the push buttons. I can also provide 14/3 shield power cable to run to the router / spindle.

sailfl

swatkins

Thanks for all your trouble Nills...

Here is what I need...

42 feet of 2 core 20 ga
42 feet of 7 core 20 ga
140 feet of 4 core 18 ga (if all one length)
35 feet of 3 core 14 ga

I looked on skycrafts website but it lists almost nothing... If they had it I could just call them and pay for it....

Thanks again
Steve

Regnar

Steve have you figured in Proximity switches? When I was there I didnt notice any 2 core shielded but I believe I read that you can use the 4 core and slice 2 get 1.

swatkins

Russell I have not gotten that far :)

I was just thinking that this stuff is hard to find, at a good price, and as long as the surplus store had some I might as well purchase what they had and get the rest later...

Nils made a good point about measuring the machine ( In a PM ) and making sure I had enough.. So I am going to follow his advice and wait a bit....

jestah

Looking for cable and wondered what core size I should get for my limits and homing switches and if its ok to run a bundle inside a single shield or if each pair needs a shield. It seems like you guys are using a single 5+ core for this task but wanted to double check.

swatkins

Steve,

I have some bad news. They have less than 50' of the 18 ga 4 shielded wire. I even looked for 18 ga 5, 6 or 7 shielded wire without any success. I will check with them when I stop in.

They do have 14/3 shield wire for power cord to spindle around .38 a ft.

They also have 20 ga 7 shielded wire.

Nills are you going to go to that store anytime soon? I picked up almost everything I needed, here in Houston, with the exception of the 7 core 20 ga and the 2 core 20 ga... I figured I could use 4 core in place of the 2 core so I am only needing the 7 core cable...

Would you have a stock number for the wire you picked up?

timberlinemd

Can someone give there opinion on this wire...
http://www.oselectronics.com/ose_p46.htm
You need to scoll down on the page to see the shielded cable

KenC

They are too thin, the "standard" here is 18AWG or 1mm2 wires when using 4.5A motor current.

timberlinemd

I read in a previous post from Gerald that he was going to recommend down grading the wire size to 21g when using motors in the 2-3 amp range. My system will be using a 35VDC power supply with the Gecko 540 driver and the PK296A2A-SG7.2 Oriental Motor. Will that wire be to small then?

bradm

Steve, it depends. If you google "awg wire current" you'll find some useful pages.
for 22AWG, one table gives 7A as a "chassis wiring" number. However, comparing that to the conservative standards we use for house wiring, you'll see that the "chassis wiring" numbers run about twice the NEC numbers (41 for 12AWG vs 20, ... ). So it appears that 3.5A from the G540 is within range for 22AWG, assuming that the wire is in good shape. However, the wire will be flexed over time, and you won't have a lot of excess safety margin.

swatkins

Would using a cable with more than 7 cores be a good Idea? I think that 7 cores are all used with the proxies and I would not have a core for the Z height setting or any other low voltage applications...

I found this wire (http://cgi.ebay.com/25-20-12cy-NuFlex-1000-Shielded-Flexible-Control-Cable_W0QQitemZ260507874567QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item3ca77ab507) with 12 cores.

Is it worth using more cores?

Gerald D

Without looking at your spec sheet, consider that you have to watch for the allowed bending radius when the cable flexes in the chain.

swatkins

This wire is rated for a bend radius of 4 x diameter... That's pretty tight :)

Gerald D

If you read carefully, you are going to find that 4 x diameter applies to a static installation......flexed once in its life only.

swatkins

Then I have a lot more to learn :(

This is the name of the wire...... 20/12cy NuFlex 1000 Shielded Flexible Control Cable

From the applications listed....Control Systems, Machine Tool , Industrial machinery,

Factory automation and drive systems.... I was thinking that it was a cable made for our purpose...

hennie

Gerald D

Steve, if all the reputable cable producers are talking of a bend radius nearer 10 to 20 times diameter, why would an unknown brand be able to offer 4 times?

swatkins

Steve, if all the reputable cable producers are talking of a bend radius nearer 10 to 20 times diameter, why would an unknown brand be able to offer 4 times?

That's the problem with today's world... Just don't know who to trust... If you read the sellers product information it seems, to the novice like myself, like this stuff is the greatest cable in the world. They cite many different manufacturing specifications and claim to meet them all...

I just did a search for the manufacture and more information... There was none to be found ... So I guess they can claim anything they want if they never have to back it up or can't even be found...

Thanks for the info Gerald :)

Gerald D

Some thing to note :I was cutting yesterday while contracrors were servicing my shutter door, they did some welding and o boy was I pissed off. Somehow the interference from the welder throwed my project out by 10 mm on the x -axis so yes there is interference on the wires.It happened while they were welding.This morning I had to redo the project and it was perfect.

The guys wanting to build plasma cutters should note this.

Hennie, I don't know how much screening/shielding you used, but I won't be surprised to hear that all your cables were shielded. Welding interference is severe and it could have gotten into your system via the mains AC power supply.

Regnar

If it is to good to be true it probably is. One of the guys on another forum thought he was buy all copper monster wire for his speakers. He ended buy steel coated in a copper film. Really low blow.

http://bbs.homeshopmachinist.net/showthread.php?t=40772

hennie

Gerald ,All the wires are shielded what I also pick up is that there is a lot of spikes in the electricity feed to the workshop that also has an effect on the computer and I do pick it up on the cut.I have a pumphouse close to me and 3 of the towns water pumps are there so everytime it starts up there is a spike.

Gerald D

Russell, I think it is hilarious that a bloke went to the cheapest store, and bought unmarked, unbranded cable and now makes a big noise that he was scammed. :D

cncb

I think the phrase "You get what you pay for" could be applied to just about any situation. :(

Regnar

Gerald you should see some of the other topics. But it does show the you get what you pay for.

KenC

It is human nature to maximise their $ value & assume too much..., There are real bargain deals out there, but that would come if one dig hard enough & know your stuff deep enough... & have some risk management in place... i.e. be reasy to get scam!
There are no free lunch...

Gerald D

And yet there is also big money to be made in creating high markups in perceived value . . . . . some people will pay over the top prices simply because of brand name or origin. Funny how it tends to be the same people who chase top names, and then go to the other end of the scale and whine at the dollar store. :)

KenC

Exactly! :mad:

Kobus_Joubert

I am happy with my GWM

Kobus el-cheapo:D

ekdenton

To me, because the wiring seemed to be the most tedious part of my build, i wanted to make sure that the wire that i purchased was from a reputable company and that even if it cost more, the chance of product failure would be lower. Or at least i hope that it will be. I started out looking for good deals in the US on the wire, and i did actually find some but it was either heavier gauge than what was specified, or had more cores than needed ect. Then I could not find one place that had more than a couple of the wires sizes which meant that i would have had to pay multiple shipping costs, in order to get everything i needed. And i did not see any specs on the cheaper wire that i can remember so it seemed in my opinion to be kind of a roll of the dice as to what quality of product i could get by price shopping or if the wire would even meet the specs that Gerald listed. So i bit the bullet and just ordered it all from the company in Germany and paid one shipping fee and it all arrived as ordered, good quality, and I hope that the extra cost will pay off. I guess only time and use of the MM will tell.

PEU

Found a source for screened flexible cables in Argentina, now I'm trying to decide which one is the right one:
http://www.marlew.com.ar/english/productos/catalogo/elecinforcom/index.php

I called the company and they suggested the EC-ARCOMP line based on my brief description of needs, but I'll do my homework comparing their offer with LAPP and other sources listed in this thread.
Datasheet: http://www.marlew.com.ar/files/pdfs_english/ec_arcomp_multiples_n23en.pdf

[EDIT] prices in pesos (divide by 4 for US dollars) http://www.electrotucuman.com.ar/carro/resultados_busqueda.php?texto=&marca=ARRAYAN&rubro=CABLES&subrubro=CABLE+COMPUTAC&pagina=1

The one I need EC0408 (18 AWG x 4 + shield) is not listed but one can infer its price from the models above and below, should be around 6 pesos/meter (USD1.5)

cerelak

dear friends.

i have a question i hope im not being stupid asking.

are all the cables sheelded???or just the cables for the 4 motors?.

domino11

Cerelak,
You need shielding on your power cables to keep the noise IN and shielding on your signal wires (estop, proxy etc) to keep the noise OUT. :)

IN-WondeR

Will Cat7 network cable be usable for the motors, when they are 4 wire motors. There are 4 pairs of wires, so the wires will be used one pair pr. wire on the motor. Do you guys think that it will be usable to power the motors?

Richards

Cat-7 cable is 23 gauge. That size wire is rated to carry 0.73A (power transmission rating). Two conductors would be able to handle up to about 1.5A if each conductor carried half the load (unlikely).

Sixteen gauge conductors are rated to handle 3.7A. Thirteen gauge wire can handle 7.4A

I have never tried using Cat-x cable for motor wiring, but I could almost bet that it would be too light-weight to do the job reliably.

On my test bench, I usually use 22-gauge cable, but the lengths are never longer than six feet. For test purposes, it works. On a machine, I would use at least 18-gauge and probably 16-gauge if possible.

gooberdog

Mike, can you explain the power transmission rating for me? I am versed in commercial wiring. That I need to go to 13ga to run 6.3 amps is hard to understand. especially when the motor leads appear almost threadlike. Any insight would be appreciated.

bradm

Well, Chuck, you see all wires aren't created equal. If you use special gold-platinum-titanium ... Whoops, I seem to have turned into a monster.

Actually, the rated current capacity of a wire of a given size is largely a function of controlling the heating or potential heating of the wire. You want to avoid having the wire heat up to the point that it has a detrimental effect on its environment, its insulation, or itself. The intended use of the wire has a lot to do with this. In the case of a traditional incandescent light bulb, we are quite happy to pump a lot of amps through a very small uninsulated wire, because the heating is acceptable in this context.

For commercial wiring, heating that causes the insulation to deteriorate over time is unacceptable, as is heating that might trigger a fire. So the amperage ratings are very conservative, for good reason. From a commercial wiring perspective, you want to be able to draw the full rated current continuously forever without any significant heating.

Now, our stepper motors actually have wires inside that are even smaller than the motor leads. However, they are assembled into windings with heat tolerant insulation (varnish), and the assembly itself acts as a heat sink within reason. This is why the motors have temperature ratings; if allowed to go to high, a insulation or a wire will melt somewhere, short, and set off a cascading failure.

But when you look at how a stepper motor is driven, it doesn't draw the full amperage continuously. It's varying all the time. So it doesn't heat the wire as much, and you can use smaller gauges than you might normally. This shows up as those threadlike motor leads.

This brings us to the last point, which is that the wires on a CNC machine undergo a fair amount of physical stress as they are dragged back and forth, and they can be fairly long. This calls for upsizing a bit to compensate for wear and resistance. 13ga for 6.3a seems a bit more than necessary, but it's consistent with Mike's engineering principles; he likes to run his motors and electronics as cool as possible, and use large wires in order to build systems that will not have failures. There is a lot of wisdom in that.

I think you would be fine with 16 or 18ga wire. Geckodrive recommends 14 or 16 gauge wire from the power supply to the drivers, and 22ga wire afterwards.

So, there ya go, 13ga at one end of the spectrum, and 22ga at the other. Pick your poison. I use 18ga.

Polder48

Thanks Brad and also Mike Richards, you both are my electronic teachers. The way you both explain these mathers are awesome and make perfectly sense to me. I'm learning and learning.

Polder

gooberdog

13ga for 6.3a seems a bit more than necessary, but it's consistent with Mike's engineering principles; he likes to run his motors and electronics as cool as possible, and use large wires in order to build systems that will not have failures. There is a lot of wisdom in that.

My first thought was "that can't be right. Mike is just going gold standard or something". So I google'd the question and came up with a chart that matched Mikes' numbers exactly. OK, this seems to be a known value. Better have someone explain this to me. Thanks Brad, you done good.

KenC

Its like selecting pipe size when you lay your plumbing... when you need a certain flow rate, (current), you don't normally choose the pipe size that is just right or smaller than it is required. a slight oversize give some guarantee on the reliability & longevity.

melissa

I'm about to place my cable order, and having difficulty making up my mind on the 4-conductor motor cables.

With my size of table and control box location, I'm looking at a 50-foot run for the the Y and Z motors.

I looked up voltage drop for DC power wiring in the technical standards published by the American Boat and Yacht Council (ABYC). They have tables for 12V, 24V and 32VDC (the most common sizes found on recreational boats).

Taking the 32VDC table, a 100 foot cable run (to the motor, and back) carrying 5 amps, for a 10% allowed voltage drop, is specified at 16 gauge. For a 3% voltage drop, the requirement is 12 gauge.

So playing a bit loose with the numbers, I'm running 35VDC to the motors, so with 16 gauge I'm already down to 31.5VDC at the motor. The tables don't specify anything smaller than 18 gauge. But I'm wondering... with 20 gauge, what's actually showing up at the farthest motors?

bradm

melissa

Michel, have you considered moving the control box closer to, or underneath the table? It might be more straightforward to have a long cable from the computer than to have long cables to the motors, spindle, sensors, and switches.

If you do go with the 50' run, I'd upsize one gauge (lower number).

Ah, there's the rub. I've already decided to mount the computer (mini-ITX) in the control box. So I'd now have to decide where to locate the keyboard, mouse, and monitor.

Hmm, there may be merit in this approach, using a KVM extender.

Zouave

So, in looking at McMaster Carr's site, I found this...

9700T41
Cable-Tray Rated Continuous-Flex Multi Cable Shielded, 18/4 AWG, 600 VAC
Quantity Per Ft.
1-99 Ft. $2.27
100 or more 1.82

This seems to be comparable or lower than some of the other prices being listed. Is this the right wire for the motors? Is there a cheaper source for it? I just got some stuff from McMaster (2 days after I ordered it) and am really happy with their shipping and products at this point. So if its a reasonable price, I'm perfectly happy with going with them. Thoughts?

Zouave

Is there a particular reason not to include the 2 core E-stop wiring with the 7-core signal wires? Is it just industry standard that it is a separate wire, dedicated to the task? It seems more economical to go with a 9/10 core wire than to have a 7 plus a 2. Am I missing something really obvious? It seems like, for the most part, they go to roughly the same spots if you position your boxes opposite the sensors for the e-stops.

Am I missing something really obvious here?

Gerald D

One of the e-stop circuits has a mains voltage (to open the contactor). You don't normally mix mains voltage and low signal voltage within the same cable over a long distance.

Zouave

That would be the obvious part that I was missing...

Thanks. :)

MetalHead

Eric are you using the 126 BOB on your build?

Zouave

Yes, I will be. Downloaded the manual a couple of days ago, am still working my way through it. Going to order that and 4 geckos 203Vs in the next day or two.

Eric are you using the 126 BOB on your build?

Brain

Hey mates,

I got in contact today with the distrubutor for Lapp kabels Croatia, and they sent me over their catalouge to check which cables i need to order.. i checked for the ölflex classic 115c in the catalouge but found only ölflex classic 115cy which by reading the product description doesnt seem to fit our needs... Now i dont know if they changed something in their brandings or the product does fit our needs, but they dont tell it to us in their data sheet because they got something "more" specialized for this purpose..

Now, im gonna copy the link to the catalouge (43 mb) its in english, so if anybody could check this i would really aprecciate it. Also, why doesnt the cables have 8 cores , but 3,4,5,7 and then 12?? I must admit that my knowledge of electicity comes down to lights on/lights off but on the other hand a man told me sometime ago that there are no dumb questions, just dumb answers :-)

I also talked with a forum member who mentioned that LiYCY cables should be my choice, i checked them out (gonna copy that link too) and by reading the description they seemed to my unknowing eye more appropriate... This data sheet is in croatian :-( but maybe you guys can figure it out by the technichal terms, they should be readable to a broader audience..

Ok here are the links:
Lapp kabel catalouge
http://www.tim-kabel.hr/images/stories/LappKabel/APPENDIX.pdf

LIYCY data sheet
http://www.tim-kabel.hr/images/stories/katalog/datasheetHRV/1101_LiYCY.pdf

Thanks in advance for the incoming wisdom ;-)

Greeting from finally a little rain but mostly hot as hell Croatia

danilom

You can use 4 cores wire. No need for 8. I had that available that is why I used it.
I got that LIYCY cable on 2 machines working 2 years now.

Brain

Just reading and learning about half coil/full coil setup... Why not 8 wires full coil? Sorry if offtopic...

danilom

Because if you looked at your drives Branko you have only 4 outputs to motors?
Bipolar drives have only that much, A and B phase. So you can lay 4 core wire to the motors and make the combination of wires at your wish there .

Brain

Still learning.. :-)

Tom Ayres

What does anyone think of the Lapp Olflex 190cy products? Are these acceptable? The current pricing seems to be less than the Olflex FD-855 and FD-855p.

Gerald D

Had a quick look at the spec and the Lapp Olflex 190cy looks quite good.

Tom Ayres

Thanks Gerald. It seems to be readily available (7 local suppliers) and cost is 20 to 30% less than some of the others.

anton

Where in SA do you get your Lapp cabling from Gerald? I am also in ct.

Alan_c

Google is your friend!!!...http://lappsouthernafrica.lappgroup.com/

hevertg

hello how about this? is not shielded, but cheap and easy to buy,

I have spent a lot of money, and it is only for a while. until you have money to spare XD

http://www.ebay.com/itm/CNC-Stepper-Motor-Hook-UP-WIRE-18-4-non-shield-Buy10-increments/290874465522?_trksid=p2047675.m1850&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%2 6asc%3D11%26meid%3D2943537027687229390%26pid%3D100 011%26prg%3D1005%26rk%3D1%26rkt%3D5%26sd%3D2603931 70662%26

Table 3000x2200
34HS9801
PMDX 122
G203V
PS-63NPR12

worth the risk?

domino11

Non shielded wire is just asking for trouble. Do you want to spend a lot of time tracking down random glitching and problems?

IN-WondeR

I wouldn't go unshielded for the motors. You will get loss of steps, and twitching in the motors and other random things when running the machine.

Use the extra Money, and get shielded cables from the start... Anything else is not worth the trouble.

KenC

U can try with unshield cable, you might get away with it fi you had done you EMI RFI protection well but are you ready for the complication?

alan254

You can add shielding to any wire. I made all my wire from single wires ( stranded wire from a overhead crane I had). I twisted the wires together as needed then added the shielding , looks like the Chinese finger game you can't your fingers out of then added a jacketing that looks like the same over that. have had on trouble at all since my machine has been running.

Al

paul60

Can anyone tell me if this cable is any good.
thanks paul.
http://www.ebay.com/itm/Shielded-Cable-Wire-4-x-18Ga-Stepper-Motor-CNC-Router-/160632659191

paul60

Can anyone tell me if this cable is any good.
thanks paul.
http://www.ebay.com/itm/Shielded-Cable-Wire-4-x-18Ga-Stepper-Motor-CNC-Router-/160632659191

smreish

its okay...but only 10' long....your going to need 20-30' of each run depending on your controller location. Plus, your steppers don't need to be shielded - only your control circuit wiring.

danilom

18 gauge is ok (0.82 mm2) only thing is the aluminium shield, I only used stranded shield
also I think there are more than 7 strands in a single wire in mine, and it should be more flexible than this one.
This looks like cables used for alarms etc... not sure how it will handle bending.

paul60

Ok thanks for the information so the stepper motors dont have to be shielded?
i was not sure.
thanks again
paul

danilom

If you take some tome to read this thread from beginning, there are some answers to you even on the first page, first 10 posts

Tom Ayres

What are you using it for? The listing doesn't show that its rated for flexing though, you may want check on that. After doing a lot of research myself, I found that the more strands per core the more durable and flexible. Price is nice though.

KenC

Usually, the strand number is proportional to flexibility of the cable. More strands per core, more flexible.

paul60

I also found this on ebay at the moment there is nothing wrong with my stepper motor cables but i been using them for over 5 years with no problem.
but would hate to have a problem and get stuck waiting for cables.
so i am going to order 100 feet to keep.
my machine is a shopbot using a Mach 3 controller that i built with allot of help
from people on this forum.
http://www.ebay.com/itm/CNC-Stepper-Motor-Hook-UP-WIRE-18-4-non-shield-Buy10-increments-/290874465522?pt=LH_DefaultDomain_0&hash=item43b9781cf2
my stepper motors are not using screened cables.
and as there is no advantage using screened cables
I will stick to unscreened
thanks again
paul

domino11

Just remember guys, that screening keeps noise in and also keeps it out. You need it on both sides of the coin. Keep the noisy signals from extending out to the sensitive control signals and to keep the sensitive control signals shielded from the noise!

hevertg

Hello, I think I found a good cable cheap and easy to buy,

http://www.mcmaster.com/#catalog/119/803/=pkutim

9700T41

Zouave

McMaster-Carr, as great as they are for getting things to you quickly, tend to have slightly higher prices overall. I have some leftover wire from my build, I sent you an e-mail, let me know if you're interested in it.

hevertg

LinuxCNC Tutorial 01 - Good Wiring Practice

I have completed the first draft of my first tutorial. I am going to attempt to paste it here, if that fails I will attach it as a PDF. I would like some feedback if you have time. Suggestions and constructive criticism to make it a better document. Any help is greatly appreciated. Hopefully when it is completed, it can be added to the list of resources on the site to help newcomers to the CNC hobby.

Joe

======================================

LinuxCNC Tutorial 1 – Good Wiring Practice (DRAFT)
Written by Joe Hildreth – www.myheap.com

When I built my first CNC machine, I didn't have a cabinet and really ran nothing more than the stepper motor controllers and power to the parallel port break out board (BOB). Later I added a touch off plate to make setting up the tool to the surface of my material easier. Wires were all over the place, components mounted to a board and away I went.

When I built my second machine, I thought I would do a neater job of things and I made a metal drawer that would slide into a computer rack and mounted all my components to it. I carefully bundled all the wires together. I even used zip tie squares to hold the wiring to the enclosure. It sure was “purdey”!

Then I decided, I would make a series of tutorials on how to locate an input pin, write the G-Code and everything else related to setting up a touch off plate for the new guys and gals out there trying to figure all this stuff out. It was during this exercise that I learned my neat and pretty wiring job was not conducive to a properly operating CNC Machine. I discovered this when I was trying to run a G38.2 linear probe command and it would stop and some random position along the way. I would restart it and it would stop again. I had to run the commands several times before the probe command would finally complete. I knew that something wasn't right, so I made a video and posted the question to the LinuxCNC forums. Within a few hours, a couple of folks on the forum had given me enough information to understand what was going on. A HUGE thank you goes to ArcEye and Andy Pugh for all the advice and suggestions they gave me. The culprit it seemed was noise.

So what is noise. Electrical noise comes from a couple of things. First is EMI (Electomagnetic Interference) caused by current flowing through wires and the second is electrical mechanical noise cause by physical switches bouncing when they open or close. Both of these conditions can cause you problems with the daily operation of your CNC machine. The mechanical noise can be dealt with pretty easily, but the EMI noise on the other hand requires a little work to help reduce and prevent it. The guidelines that follow are some things that you can do to reduce this problem. Before we get to the list of things to do, let's first discuss a little more what EMI is.

EMI as I stated above is caused by current running through a wire, but there is a little more to it. When current runs through a wire a magnetic field is created. As the current builds the magnetic field gets stronger. Then when the current ceases to flow through the wire the magnetic field collapses. This in itself isn't too bad, but if this magnetic field happens to cross another wire it will induce a voltage across it. This is how a transformer works. It uses a magnetic field in one coil of wire to induce a voltage in another coil of wire. If a wire is able to induce a voltage across another wire that we are using for a signal at logic level voltages, it may drive the voltage level in that wire to some state that the logic circuits reading it cannot understand. To be clear, 5V TTL work on distinctive voltage ranges. An input voltage of 0V to .8V is considers a false or low logic level. A voltage level of about 2V to 5V is read as a true or high level input. If however a voltage somewhere in between the .8V and 2V is on the input then we do not know what the output will be. When an input in this range is given the output could be either a high or a low level and this has to be avoided for a reliable circuit. Knowing the above information we know that a magnetic field crossing our signal wires could drive the input voltage to a TTL circuit into this band resulting in unexpected operation. But this is only half the story.

When current is switched on and off in a circuit we know that it creates a magnetic field but when current is switched on and off repeatedly it is possible to create another kind of noise. If the rate the current is being switched on and off is fast enough, it can generate radio frequencies that can interfere with other equipment nearby. The strength of these radio frequencies again depends on the amount of current that flows through the wire.

Now that we know what EMI is and the effects that it can have let's discuss what we can do about it by giving some general wiring tips.

AC Line Voltage

The AC that you use can inject noise into your power supplies and other equipment. If you have motors running on the same circuit for example, can create noise on the line if it is running on the same circuit as your CNC components. RF signals can also be superimposed onto AC line voltage. Years ago, this fact was exploited in some home entertainment systems to provide music to a remote speaker over the AC line. In-line filters are made to attenuate (reduce or block) this type of noise from the AC line voltage before it is run into your equipment. AC Line Filters can be found at electronic supply houses. LinuxCNC forum user “lead_injection” recommends Medical Grade filters as they have the lowest leakage current.

PSU's (Power Supply Units)

1. AC Grounds

A typical CNC machine may have a few different power supplies installed and in use on the system. Make sure the AC inputs to your power supplies are properly grounded. Tie them all to the same ground. Many power supplies have a metal case and the case is usually tied to the AC ground as well so keep this in mind when you are fastening them down. In my case I have a metal drawer that I am using, so when I fasten down the power supplies, I need to keep in mind that the AC ground will be attached to this drawer as well.

2. DC Grounds

There are two trains of thought when it comes to the DC ground. Some folks say that you should ground it to the AC ground and others suggest that you should create a separate isolated ground plane for the DC power. I don't know if one style is better than another but if you are interested a Google search you can find folks that will defend either side of the argument.

Additionally, many suggest that you keep the ground for any supply providing logic level voltages segregated from any other DC supply to prevent ground loops which could create new additional problems. A ground loop exists when the grounds of two different devices are at different potentials. For example, if the PSU for your drivers were at a different potential than your supply for your logic and you tied them together, you could corrupt your logic signals by a small voltage change. If this difference in voltage is enough to push your signal into the unknown state we discussed above, then your equipment will be unreliable or possibly erratic.

In my controller drawer I have three PSU's. Two of them are 36VDC and one is a 5VDC. The 36V supplies are meant to run my stepper controllers while the 5V supply will provide power to my BOB and TTL signal level voltages. My intention is to give the 36V their own ground plane and to isolate the 5V supply for the logic.

3. DC Supply wires

When running power to various pieces of equipment in your electronics box, using twisted pairs will aid in negating noise from neighboring wires. The twist in the wire creates a canceling effect on any magnetic field that passes across them. For additional protection use twisted wire that is housed in a shielded jacket. This type of wire typically has a metal foil or braid wrapped around the wire along with a stranded wire that runs beside it. The foil or braid will absorb the magnetic field that a neighboring wire produces as current runs through it. For best results, attach the stranded wire to the DC ground. Doing this will prevent the field from passing beyond the shielding to affect the wires contained in the cable. When grounding the shield wire, only ground at one end. Grounding the shield wire at both ends can create a loop that can effectively negate the ground allowing noise to be injected back into the wire.

Stepper Motor Controllers

When wiring the controllers up, the following list should be helpful.

1. The metal housing of the controller should be grounded. You can verify this with a multimeter set to check continuity. Best practice is to mount your controllers directly to your ground plane. The ground plane as you recall from above is an isolated piece of metal that you will attach the ground from your PSU that supplies your controllers. A simple way of doing this is to use a piece of aluminum plate for the ground plane and mount it to your enclosure using insulated standoffs. Mounting your controllers to this plane allows any noise the controller might generate to be diverted to ground rather than emitted through the air and possibly affecting surrounding equipment.

2. The controllers that I have experience with have two sets of connectors. They are divided into two groups. The first group is power supply and motor leads. The second group are control signals. When wiring your controllers keep these two groups separated. Run your power and motor leads to one side of the controller and the signal wires to the other if at all possible. Again, using shielded wire will take you a long way in avoiding extraneous noise.

3. When making power connections to the controller use a twisted pair of wires. You can twist them yourself, but make sure you have at least one twist per inch of wire. For best protection use a shielded twisted pair and attach one end of the shield wire to your grounding plane. The piece of aluminum plate your controllers are mounted to.

4. When making connections to the motors, use shielded cable. These wires carry the most current and will emit a lot of magnetic radiation. Be sure to ground the shield wire to the ground plane.

5. When making signal connections to the controller (The step and direction pins) use a twisted pair to make the connection. Category 5 Ethernet cable is cheap and contains four twisted pairs. This makes excellent signal wire. You can strip the housing back enough that you can run two pair to one controller and another two pair to a second controller. You can also by Ethernet cable with a shield. If you ground this shield, be sure to ground it to the PSU that supplies your logic signals and not to the power plane for your stepper controller and its PSU.

Variable Frequency Drives (VFDs)

VFDs are used to drive spindles and work by varying the frequency of the AC going to the spindle. VFDs are great noise producers. If at all possible locate your VFD in a separate enclosure or cabinet to reduce the risk of it injecting noise into your other wiring. Recommended wiring for the VFD is foil braid or copper tape shielded wire and observing good grounding practices. A PDF document from Belden on the topic can be found at the following URL.

www.mc-mc.com/Portals/1/articles/WP-VFDCablingPractices.pdf

Wire Selection and Use

Wire comes in many types, sizes and configurations. Wading through all the wire available is a monumental task of its own, but for our purposes we only have a look at the types of wires suitable for wiring you a CNC controller. Additionally, how the wire is to be used can have some affect on the overall system. What follows are some tips that may prove helpful.

1. Shielded Wire.

There are basically three types of shielded wire. One has a bare wire braid that surrounds the wire inside, and the other has metal foil that surrounds the wire inside. And lastly, there is both a braid and metal foil. All of these are designed to prevent noise from being injected into the wire enclosed. The type of shielded wire you will select will depend on the amount of noise you are trying to combat. A brief discussion of each follows.

A) Foil Shielded Wire

Foil shielded wire has a thin metal aluminum foil that is usually bonded to a film of plastic that surrounds the wire. The enclosed wire is usually 100% covered and that is good. Foil shielded wire can be difficult to use, especially when trying to attach a connector to the shielding in order to ground it. For this reason, you will usually find a bar metal stranded wire enclosed that you can make a connection to. Of the three types of shielded wire, this is the least effective.

Braided Shielded Wire

Braided Shielded Wire has a metal braid that surrounds the wire. It is more bulky than the foil shielded wire and does not provide 100% coverage. It typically covers 70 to 95% covering depending on how tight the braid is made. The braid is typically made of tinned copper wire. Because copper is a better conductor than aluminum and it's bulky size it works better to shield the wire than the foil shielded wire. It should be noted that this type of shielded wire will cost more than the foil shielded wire above. Of the three types this one is more effective than foil shielded wire, but less effective than the next one discussed.

C) Multi Shielded Wire

For very noisy environments a wire that contains both foil wrapped wire and a braid will provide the most protection. As you can guess, of the three types this is the most expensive.

2. Routing Wire

There are two types of routed wire. Wire that is stationary and wire that gets moved as the machine runs. Along with this, we must consider the effects of neighboring wires to the wire being routed may have. The following recommendations were given by forum member lead_injection.

A) Routing Movable Wires

Any wire that will be moved about in normal operation of the CNC falls into this category. For example, the wires that run from your controllers through cable management and then to your motors.

If you are flexing your cables, use high flex rated cable (IGUS). This may get pricey for 4pair STP type cables.

If running cables in a cabletrack/carrier tie them down at both ends of the cable track. If not, ratcheting can occur and fatigue the cable prematurely.

In a cabletrack/carrier observe the neutral axis idea. Have the wire run as close to the neutral axis as possible. Make sure the wire is not in tension in the longest neutral axis situation.

Routing Stationary Wires

Running different signal classes (high voltage and low voltage) in metal conduit may make the noise worse. Separate by as much distance as possible and if they have to cross, cross them at 90 degree angles.

Avoid wiring loops coming off of devices - they are great antennas for receiving noise, or great antennas for transmitting noise. Run wires along the ground plane.

Signal Wires

The wires that are used to transmit logic signals are the most susceptible to noise interference. The reason for this is the low level voltages that are used to convey the information. The following will prove helpful in keeping your signal wires clean.

1. Isolate the PSU for your signal wires from the rest of the system. Keeping the power supply isolated will prevent your other supplies from interfering with it.

2. Use twisted pairs to carry your signals. For best results use both wires and do not share a common ground for two or more signals. Use a pair of wires for each signal. Using shielded wire is best. When grounding the shield wire, ground to the logic PSU.

3. Shielded Twisted Pairs (STP) are most beneficial to differential signals. If you add the noise to both signals, the common point is not affected - the magnitude of the difference is maintained.

Stranded Wire

Wire comes in two forms, solid conductor and stranded. Both have their ups and downs. Stranded wire is pretty common in cables because it is more flexible. When using any stranded wire keep the following things in mind.

1. Terminate the ends

Little wires hanging off the end of your cable can create problems. They can cause shorts when wired next to other wires in close proximity or to the boards they are connected to. They can also act like a little antenna that will help them emit any noise they may be trying to generate. There are several ways that you can terminate them.

A) Twist and solder the ends. Tinning the wires in this manner makes then easier to insert in the set screw connectors and binds all the little wires together preventing them from fraying apart.

Use crimp on ends. Crimp on ends like spade connectors or bootlace ferrules also work very well. It is best to not to tin the end before crimping them. Tinning the wires could allow them to loosen over time. Attention to detail and the proper selection of the crimped end will form a quality mechanical connection.

2. Be careful of the amount of insulation you strip from the wire. Stripping too much insulation off will lead to exposed wire that something can short against. If you do simply trim off the extra wire.

Control Signals

When a limit or home switch is engaged, or a probe has made or broken contact, we use this signal to signify the event has taken place. Typically this is done by using input pins on the parallel port. The signal voltages used on the port are in the 3 to 5 volt range depending on the type of port you have. It only takes a small noise injected onto the signal wires to put it in that unknown voltage area we discussed above, resulting in an unknown TTL state. If after careful wiring and planning you are still having these kind of issues, there are a couple of things you can do to fix the problem.

1. Higher control voltages. If instead of using the logic PSU to supply the voltage for the detection circuit you used a larger PSU, for example a 12 or 24V supply to the input side of a mechanical relay or SSR (solid state relay), the control circuit would be less affected by noise. In turn, the mechanical relay or SSR would turn on or off the control signal to your parallel port or breakout board allowing you to keep these small control voltages in short runs and contained in your wiring cabinet. In addition you may be able to find opto-isolators or opto-couplers that will work on higher input voltages that will switch the lower TTL voltages to the port. A search on Jameco, Mouser or other electronics supplier should turn something up.

2. Higher control current. If you are using pull up resistors on your inputs, you can use a smaller valued resistor to increase the current draw and reduce the chance of a false signal. Keep in mind the additional current load on your PSU. You can calculate the current load with a judicious application of Ohm's Law.

Mechanical Noise

Mechanical Noise happens when mechanical contacts open and close, as in a switch or relay contacts. As they open or close they will bounce against each other creating a rapid state change in the circuit. The electronics monitoring the change in state, the opening and closing of the contacts, can detect these quick changes. Sometimes it doesn't matter, but more often than not, you don't what this condition to interfere with the operation of your machine. For example, it will generate errors when probing. However, like I mentioned above, this situation is pretty easy to remedy.

1. Debouncing a switch with hardware.

Debouncing a switch can be done with the addition of some hardware to the signal circuit. There are ICs (Integrated Circuits) like Motorola's MC14490 that are designed to do just this thing, but they can be difficult to find. A simple method of debouncing a SPST switch uses an RC network (sometimes coupled with a diode to increase the speed) as a delay into a Schmitt triggered inverter allowing it to compensate for the time it takes the switch to settle down. If you are interested in this method, you can find more information on the subject by visiting the following URL:

electrosome.com/switch-debouncing/

Additionally a great video on debouncing a SPST switch can be found here:

I may at a later time create a tutorial on how these circuits are made, but there is an easier way. That comes next.

2. Debouncing a switch with HAL

The hardware abstraction layer (HAL) of LinuxCNC has a Debounce component. The Debounce component has a single input pin and a single output pin. Its job is to look at the input and to send the output after a programmed delay time. The Debounce HAL component will be covered in a separate tutorial when we create a touchoff plate for the CNC machine. More information can be found for the Debounce component by visiting the following URLs:

linuxcnc.org/docs/html/hal/rtcomps.html#sec:Debounce
linuxcnc.org/docs/html/man/man9/debounce.9.html

Documentation

Documenting your wiring cannot be over stressed. With power feeds, motor leads, signal wire and everything else you stuffed into your your wiring compartment, you will be grateful that you documented your wiring. A year after you completed your CNC wiring and you want to add something, or some trouble arises, you will have your documentation to fall back on.

So, what should you document? The list that follows probably should be the minimum you hang onto and if you think you should note or save something else, you probably should.

1. Hardware Documentation.

At a minimum, make sure you save any documentation you have for your hardware in a safe place. Stepper controllers, Break out Boards, Power Supplies, PID controllers, individual components if they apply, Servo Controllers, etc. Although it takes a little more room, I print all the electronic documentation for the stuff I have and keep them in a binder in plastic sheet protectors. This binder is divided into sections based on the type of hardware or documentation I am keeping.

2. Wiring Schematics

As you wire your CNC, make sure to draw up a schematic that you can reference later. The schematic does not have to be all that neat, but you must be able to pick it up a year later and understand what you have done. Be sure to annotate your schematic with any additional information that will help remind you of what you made. Keep a copy of your schematics in your documentation folder so it does not get lost. If you keep things electronically, scan your schematics and save it with the rest of your documents. If you don't have a scanner, you can take a digital picture and save it to your computer.

3. Label your wires

Take the time to label your wires. When you start bundling wires, it is hard to look at them and know for sure what is what when you go back to modify or change something a year later. Label your motor wires with the joint or axis they run, label your signal wires so you know what they do. The idea here is to make it easy to identify a specific wire or set of wires you have in your controller.

Additional Information

1. LinuxCNC and Machine Related Questions

Additional Information and help can be found by using the LinuxCNC forums. If you are not a member of these forums, I encourage you to join. Please visit:

linuxcnc.org/index.php/english/forum/index

The folks there are very helpful, have loads of experience and are willing to share some insights.

2. Cable and Wire Harness Assemblies

Publication IPC/WHMA-A-620 covers the Requirements and Acceptance for Cable and Wire Harness Assemblies. This publication describes acceptability criteria for producing crimped, mechanically secured, or soldered interconnections and the associated lacing/restraining criteria associated with cable and harness assemblies. It is not the intent of this document to exclude any acceptable procedure used to make the electrical connection. A 2002 version of this document can be downloaded from the following URL.

www.gartechenterprises.com/downloads/IPC-A-620.pdf

3. Understanding EMC (Electromagnetic Compatibility) Phenomena

A publication from Groupe Schneider goes into depth about what Electromagnetic interference is and how to design your system with it in mind. This is a great document is you want to know the what and why of electromagnetic interference. It discusses in detail, cables, grounds, types of interference, chassis connections, filters and more. A very good source of information to those who want to know more on the topic. You can download a copy of the 200+ page PDF from the following URL:

www.engineering.schneider-electric.dk/At...ty_install_guide.pdf

Acknowledgements

I would like to thank the following people from the LinuxCNC forums for their input on this tutorial. It is with their help I am able to give you the information contained herein.

Andy Pugh
ArcEye
Clive S.
Jake
lead_injection
Peter Ommen

(End of Tutorial)

Hello all,I have completed the first draft of my first tutorial. I am going to attempt to paste it here, if that fails I will attach it as a PDF. I would like some feedback if you have time. Suggestions and constructive criticism to make it a better document. Any help is greatly appreciated. Hopefully when it is completed, it can be added to the list of resources on the site to help newcomers to the CNC hobby.Joe======================================When I built my first CNC machine, I didn't have a cabinet and really ran nothing more than the stepper motor controllers and power to the parallel port break out board (BOB). Later I added a touch off plate to make setting up the tool to the surface of my material easier. Wires were all over the place, components mounted to a board and away I went.When I built my second machine, I thought I would do a neater job of things and I made a metal drawer that would slide into a computer rack and mounted all my components to it. I carefully bundled all the wires together. I even used zip tie squares to hold the wiring to the enclosure. It sure was “purdey”!Then I decided, I would make a series of tutorials on how to locate an input pin, write the G-Code and everything else related to setting up a touch off plate for the new guys and gals out there trying to figure all this stuff out. It was during this exercise that I learned my neat and pretty wiring job was not conducive to a properly operating CNC Machine. I discovered this when I was trying to run a G38.2 linear probe command and it would stop and some random position along the way. I would restart it and it would stop again. I had to run the commands several times before the probe command would finally complete. I knew that something wasn't right, so I made a video and posted the question to the LinuxCNC forums. Within a few hours, a couple of folks on the forum had given me enough information to understand what was going on. A HUGE thank you goes to ArcEye and Andy Pugh for all the advice and suggestions they gave me. The culprit it seemed was noise.So what is noise. Electrical noise comes from a couple of things. First is EMI (Electomagnetic Interference) caused by current flowing through wires and the second is electrical mechanical noise cause by physical switches bouncing when they open or close. Both of these conditions can cause you problems with the daily operation of your CNC machine. The mechanical noise can be dealt with pretty easily, but the EMI noise on the other hand requires a little work to help reduce and prevent it. The guidelines that follow are some things that you can do to reduce this problem. Before we get to the list of things to do, let's first discuss a little more what EMI is.EMI as I stated above is caused by current running through a wire, but there is a little more to it. When current runs through a wire a magnetic field is created. As the current builds the magnetic field gets stronger. Then when the current ceases to flow through the wire the magnetic field collapses. This in itself isn't too bad, but if this magnetic field happens to cross another wire it will induce a voltage across it. This is how a transformer works. It uses a magnetic field in one coil of wire to induce a voltage in another coil of wire. If a wire is able to induce a voltage across another wire that we are using for a signal at logic level voltages, it may drive the voltage level in that wire to some state that the logic circuits reading it cannot understand. To be clear, 5V TTL work on distinctive voltage ranges. An input voltage of 0V to .8V is considers a false or low logic level. A voltage level of about 2V to 5V is read as a true or high level input. If however a voltage somewhere in between the .8V and 2V is on the input then we do not know what the output will be. When an input in this range is given the output could be either a high or a low level and this has to be avoided for a reliable circuit. Knowing the above information we know that a magnetic field crossing our signal wires could drive the input voltage to a TTL circuit into this band resulting in unexpected operation. But this is only half the story.When current is switched on and off in a circuit we know that it creates a magnetic field but when current is switched on and off repeatedly it is possible to create another kind of noise. If the rate the current is being switched on and off is fast enough, it can generate radio frequencies that can interfere with other equipment nearby. The strength of these radio frequencies again depends on the amount of current that flows through the wire.Now that we know what EMI is and the effects that it can have let's discuss what we can do about it by giving some general wiring tips.The AC that you use can inject noise into your power supplies and other equipment. If you have motors running on the same circuit for example, can create noise on the line if it is running on the same circuit as your CNC components. RF signals can also be superimposed onto AC line voltage. Years ago, this fact was exploited in some home entertainment systems to provide music to a remote speaker over the AC line. In-line filters are made to attenuate (reduce or block) this type of noise from the AC line voltage before it is run into your equipment. AC Line Filters can be found at electronic supply houses. LinuxCNC forum user “lead_injection” recommends Medical Grade filters as they have the lowest leakage current.1. AC GroundsA typical CNC machine may have a few different power supplies installed and in use on the system. Make sure the AC inputs to your power supplies are properly grounded. Tie them all to the same ground. Many power supplies have a metal case and the case is usually tied to the AC ground as well so keep this in mind when you are fastening them down. In my case I have a metal drawer that I am using, so when I fasten down the power supplies, I need to keep in mind that the AC ground will be attached to this drawer as well.2. DC GroundsThere are two trains of thought when it comes to the DC ground. Some folks say that you should ground it to the AC ground and others suggest that you should create a separate isolated ground plane for the DC power. I don't know if one style is better than another but if you are interested a Google search you can find folks that will defend either side of the argument.Additionally, many suggest that you keep the ground for any supply providing logic level voltages segregated from any other DC supply to prevent ground loops which could create new additional problems. A ground loop exists when the grounds of two different devices are at different potentials. For example, if the PSU for your drivers were at a different potential than your supply for your logic and you tied them together, you could corrupt your logic signals by a small voltage change. If this difference in voltage is enough to push your signal into the unknown state we discussed above, then your equipment will be unreliable or possibly erratic.In my controller drawer I have three PSU's. Two of them are 36VDC and one is a 5VDC. The 36V supplies are meant to run my stepper controllers while the 5V supply will provide power to my BOB and TTL signal level voltages. My intention is to give the 36V their own ground plane and to isolate the 5V supply for the logic.3. DC Supply wiresWhen running power to various pieces of equipment in your electronics box, using twisted pairs will aid in negating noise from neighboring wires. The twist in the wire creates a canceling effect on any magnetic field that passes across them. For additional protection use twisted wire that is housed in a shielded jacket. This type of wire typically has a metal foil or braid wrapped around the wire along with a stranded wire that runs beside it. The foil or braid will absorb the magnetic field that a neighboring wire produces as current runs through it. For best results, attach the stranded wire to the DC ground. Doing this will prevent the field from passing beyond the shielding to affect the wires contained in the cable. When grounding the shield wire, only ground at one end. Grounding the shield wire at both ends can create a loop that can effectively negate the ground allowing noise to be injected back into the wire.When wiring the controllers up, the following list should be helpful.1. The metal housing of the controller should be grounded. You can verify this with a multimeter set to check continuity. Best practice is to mount your controllers directly to your ground plane. The ground plane as you recall from above is an isolated piece of metal that you will attach the ground from your PSU that supplies your controllers. A simple way of doing this is to use a piece of aluminum plate for the ground plane and mount it to your enclosure using insulated standoffs. Mounting your controllers to this plane allows any noise the controller might generate to be diverted to ground rather than emitted through the air and possibly affecting surrounding equipment.2. The controllers that I have experience with have two sets of connectors. They are divided into two groups. The first group is power supply and motor leads. The second group are control signals. When wiring your controllers keep these two groups separated. Run your power and motor leads to one side of the controller and the signal wires to the other if at all possible. Again, using shielded wire will take you a long way in avoiding extraneous noise.3. When making power connections to the controller use a twisted pair of wires. You can twist them yourself, but make sure you have at least one twist per inch of wire. For best protection use a shielded twisted pair and attach one end of the shield wire to your grounding plane. The piece of aluminum plate your controllers are mounted to.4. When making connections to the motors, use shielded cable. These wires carry the most current and will emit a lot of magnetic radiation. Be sure to ground the shield wire to the ground plane.5. When making signal connections to the controller (The step and direction pins) use a twisted pair to make the connection. Category 5 Ethernet cable is cheap and contains four twisted pairs. This makes excellent signal wire. You can strip the housing back enough that you can run two pair to one controller and another two pair to a second controller. You can also by Ethernet cable with a shield. If you ground this shield, be sure to ground it to the PSU that supplies your logic signals and not to the power plane for your stepper controller and its PSU.VFDs are used to drive spindles and work by varying the frequency of the AC going to the spindle. VFDs are great noise producers. If at all possible locate your VFD in a separate enclosure or cabinet to reduce the risk of it injecting noise into your other wiring. Recommended wiring for the VFD is foil braid or copper tape shielded wire and observing good grounding practices. A PDF document from Belden on the topic can be found at the following URL.Wire comes in many types, sizes and configurations. Wading through all the wire available is a monumental task of its own, but for our purposes we only have a look at the types of wires suitable for wiring you a CNC controller. Additionally, how the wire is to be used can have some affect on the overall system. What follows are some tips that may prove helpful.1. Shielded Wire.There are basically three types of shielded wire. One has a bare wire braid that surrounds the wire inside, and the other has metal foil that surrounds the wire inside. And lastly, there is both a braid and metal foil. All of these are designed to prevent noise from being injected into the wire enclosed. The type of shielded wire you will select will depend on the amount of noise you are trying to combat. A brief discussion of each follows.A) Foil Shielded WireFoil shielded wire has a thin metal aluminum foil that is usually bonded to a film of plastic that surrounds the wire. The enclosed wire is usually 100% covered and that is good. Foil shielded wire can be difficult to use, especially when trying to attach a connector to the shielding in order to ground it. For this reason, you will usually find a bar metal stranded wire enclosed that you can make a connection to. Of the three types of shielded wire, this is the least effective.Braided Shielded WireBraided Shielded Wire has a metal braid that surrounds the wire. It is more bulky than the foil shielded wire and does not provide 100% coverage. It typically covers 70 to 95% covering depending on how tight the braid is made. The braid is typically made of tinned copper wire. Because copper is a better conductor than aluminum and it's bulky size it works better to shield the wire than the foil shielded wire. It should be noted that this type of shielded wire will cost more than the foil shielded wire above. Of the three types this one is more effective than foil shielded wire, but less effective than the next one discussed.C) Multi Shielded WireFor very noisy environments a wire that contains both foil wrapped wire and a braid will provide the most protection. As you can guess, of the three types this is the most expensive.2. Routing WireThere are two types of routed wire. Wire that is stationary and wire that gets moved as the machine runs. Along with this, we must consider the effects of neighboring wires to the wire being routed may have. The following recommendations were given by forum member lead_injection.A) Routing Movable WiresAny wire that will be moved about in normal operation of the CNC falls into this category. For example, the wires that run from your controllers through cable management and then to your motors.If you are flexing your cables, use high flex rated cable (IGUS). This may get pricey for 4pair STP type cables.If running cables in a cabletrack/carrier tie them down at both ends of the cable track. If not, ratcheting can occur and fatigue the cable prematurely.In a cabletrack/carrier observe the neutral axis idea. Have the wire run as close to the neutral axis as possible. Make sure the wire is not in tension in the longest neutral axis situation.Routing Stationary WiresRunning different signal classes (high voltage and low voltage) in metal conduit may make the noise worse. Separate by as much distance as possible and if they have to cross, cross them at 90 degree angles.Avoid wiring loops coming off of devices - they are great antennas for receiving noise, or great antennas for transmitting noise. Run wires along the ground plane.The wires that are used to transmit logic signals are the most susceptible to noise interference. The reason for this is the low level voltages that are used to convey the information. The following will prove helpful in keeping your signal wires clean.1. Isolate the PSU for your signal wires from the rest of the system. Keeping the power supply isolated will prevent your other supplies from interfering with it.2. Use twisted pairs to carry your signals. For best results use both wires and do not share a common ground for two or more signals. Use a pair of wires for each signal. Using shielded wire is best. When grounding the shield wire, ground to the logic PSU.3. Shielded Twisted Pairs (STP) are most beneficial to differential signals. If you add the noise to both signals, the common point is not affected - the magnitude of the difference is maintained.Wire comes in two forms, solid conductor and stranded. Both have their ups and downs. Stranded wire is pretty common in cables because it is more flexible. When using any stranded wire keep the following things in mind.1. Terminate the endsLittle wires hanging off the end of your cable can create problems. They can cause shorts when wired next to other wires in close proximity or to the boards they are connected to. They can also act like a little antenna that will help them emit any noise they may be trying to generate. There are several ways that you can terminate them.A) Twist and solder the ends. Tinning the wires in this manner makes then easier to insert in the set screw connectors and binds all the little wires together preventing them from fraying apart.Use crimp on ends. Crimp on ends like spade connectors or bootlace ferrules also work very well. It is best to not to tin the end before crimping them. Tinning the wires could allow them to loosen over time. Attention to detail and the proper selection of the crimped end will form a quality mechanical connection.2. Be careful of the amount of insulation you strip from the wire. Stripping too much insulation off will lead to exposed wire that something can short against. If you do simply trim off the extra wire.When a limit or home switch is engaged, or a probe has made or broken contact, we use this signal to signify the event has taken place. Typically this is done by using input pins on the parallel port. The signal voltages used on the port are in the 3 to 5 volt range depending on the type of port you have. It only takes a small noise injected onto the signal wires to put it in that unknown voltage area we discussed above, resulting in an unknown TTL state. If after careful wiring and planning you are still having these kind of issues, there are a couple of things you can do to fix the problem.1. Higher control voltages. If instead of using the logic PSU to supply the voltage for the detection circuit you used a larger PSU, for example a 12 or 24V supply to the input side of a mechanical relay or SSR (solid state relay), the control circuit would be less affected by noise. In turn, the mechanical relay or SSR would turn on or off the control signal to your parallel port or breakout board allowing you to keep these small control voltages in short runs and contained in your wiring cabinet. In addition you may be able to find opto-isolators or opto-couplers that will work on higher input voltages that will switch the lower TTL voltages to the port. A search on Jameco, Mouser or other electronics supplier should turn something up.2. Higher control current. If you are using pull up resistors on your inputs, you can use a smaller valued resistor to increase the current draw and reduce the chance of a false signal. Keep in mind the additional current load on your PSU. You can calculate the current load with a judicious application of Ohm's Law.Mechanical Noise happens when mechanical contacts open and close, as in a switch or relay contacts. As they open or close they will bounce against each other creating a rapid state change in the circuit. The electronics monitoring the change in state, the opening and closing of the contacts, can detect these quick changes. Sometimes it doesn't matter, but more often than not, you don't what this condition to interfere with the operation of your machine. For example, it will generate errors when probing. However, like I mentioned above, this situation is pretty easy to remedy.1. Debouncing a switch with hardware.Debouncing a switch can be done with the addition of some hardware to the signal circuit. There are ICs (Integrated Circuits) like Motorola's MC14490 that are designed to do just this thing, but they can be difficult to find. A simple method of debouncing a SPST switch uses an RC network (sometimes coupled with a diode to increase the speed) as a delay into a Schmitt triggered inverter allowing it to compensate for the time it takes the switch to settle down. If you are interested in this method, you can find more information on the subject by visiting the following URL:Additionally a great video on debouncing a SPST switch can be found here:I may at a later time create a tutorial on how these circuits are made, but there is an easier way. That comes next.2. Debouncing a switch with HALThe hardware abstraction layer (HAL) of LinuxCNC has a Debounce component. The Debounce component has a single input pin and a single output pin. Its job is to look at the input and to send the output after a programmed delay time. The Debounce HAL component will be covered in a separate tutorial when we create a touchoff plate for the CNC machine. More information can be found for the Debounce component by visiting the following URLs:Documenting your wiring cannot be over stressed. With power feeds, motor leads, signal wire and everything else you stuffed into your your wiring compartment, you will be grateful that you documented your wiring. A year after you completed your CNC wiring and you want to add something, or some trouble arises, you will have your documentation to fall back on.So, what should you document? The list that follows probably should be the minimum you hang onto and if you think you should note or save something else, you probably should.1. Hardware Documentation.At a minimum, make sure you save any documentation you have for your hardware in a safe place. Stepper controllers, Break out Boards, Power Supplies, PID controllers, individual components if they apply, Servo Controllers, etc. Although it takes a little more room, I print all the electronic documentation for the stuff I have and keep them in a binder in plastic sheet protectors. This binder is divided into sections based on the type of hardware or documentation I am keeping.2. Wiring SchematicsAs you wire your CNC, make sure to draw up a schematic that you can reference later. The schematic does not have to be all that neat, but you must be able to pick it up a year later and understand what you have done. Be sure to annotate your schematic with any additional information that will help remind you of what you made. Keep a copy of your schematics in your documentation folder so it does not get lost. If you keep things electronically, scan your schematics and save it with the rest of your documents. If you don't have a scanner, you can take a digital picture and save it to your computer.3. Label your wiresTake the time to label your wires. When you start bundling wires, it is hard to look at them and know for sure what is what when you go back to modify or change something a year later. Label your motor wires with the joint or axis they run, label your signal wires so you know what they do. The idea here is to make it easy to identify a specific wire or set of wires you have in your controller.1. LinuxCNC and Machine Related QuestionsAdditional Information and help can be found by using the LinuxCNC forums. If you are not a member of these forums, I encourage you to join. Please visit:The folks there are very helpful, have loads of experience and are willing to share some insights.2. Cable and Wire Harness AssembliesPublication IPC/WHMA-A-620 covers the Requirements and Acceptance for Cable and Wire Harness Assemblies. This publication describes acceptability criteria for producing crimped, mechanically secured, or soldered interconnections and the associated lacing/restraining criteria associated with cable and harness assemblies. It is not the intent of this document to exclude any acceptable procedure used to make the electrical connection. A 2002 version of this document can be downloaded from the following URL.3. Understanding EMC (Electromagnetic Compatibility) PhenomenaA publication from Groupe Schneider goes into depth about what Electromagnetic interference is and how to design your system with it in mind. This is a great document is you want to know the what and why of electromagnetic interference. It discusses in detail, cables, grounds, types of interference, chassis connections, filters and more. A very good source of information to those who want to know more on the topic. You can download a copy of the 200+ page PDF from the following URL:I would like to thank the following people from the LinuxCNC forums for their input on this tutorial. It is with their help I am able to give you the information contained herein.Andy PughArcEyeClive S.Jakelead_injectionPeter Ommen

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