Looking at the wires that come in the lowrider kit I know I’m going to need more for my build. Has anyone used Cat 5 cables for their wires? I happen to have a bulk spool… They’re probably around the same size and they’re shielded and wrapped in a nice sheathing that will wear well I would imagine. I’m not sure if the twist adds interference or if they’re undersized or something.
This question came up in a topic recently, but my searches are not finding it. Most Cat 5 cable is solid core wire not stranded wire. The concern was that solid core wire would fatigue and break if used in any part of the rig where the wire is regularly moved.
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Thanks, I searched but didn’t come up with anything so I thought I’d ask. Perhaps I’ll try it to start and plan to replace them shortly with something better.
I just did a quick search on Amazon, and ethernet patch cables are relatively cheap. For example here is 50’ of Cat6 patch cable for $15. These cables should use stranded wire, and I believe Cat6 call for 23 gauge wire which should work well for the steppers. I don’t know if there is any benefit to this kind of wire over a roll of ribbon wire.
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I used cat5 to rewire mine.
On a much older, non-MPCNC build I used cat-5 but used both wires of a pair for each motor lead. That machine used nema23 motors so I was a bit worried abou amperage. Never had a problem but haven’t used that machine now for several years.
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Given that I have several boxes of Cat5…
I used some for the wire runs that do not need to flex. These include the runs from the motors and limit switches on the “B” side, where the wire goes from the motor (or switch) into the steel tube of the gantry. Once established, the wire here should never need to flex. I then used duPont connectors to connect to the wires from the wiring kit, which are stranded wire.
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I came across this a while back, so it has been tried before but nothing on how well it worked for him… maybe a pm will get him to answer your question?
I ran my MPCNC with cat 5e and RJ45 keystone jacks for a while. It worked but… as the machine moved the connectors would lose connection and cause the motors to stutter. Ruined a good number of projects. So I replaced all the connectors with DuPont ones.
Then I noticed that the stiff network cable sleeve was causing too much resistance in my drag chain (and later my) tape measure cable guide. It would cause the motors to skip steps because they would be over powered. Too much resistance with the drag chain and the bit cutting wood. So I had to strip all the cable shielding off and expose the twisted pairs. I also upped the amps to my motors in firmware. That solved it for a while.
Then I started having issues with the solid cores breaking. And I had a stepper motor burn out. Rare occurrence but I confirmed that it happened.
So I swapped all those cables out for 22 awg stranded ribbon cables that I found cheap online.
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Consensus is that you need to use stranded “patch” cables rather than solid core “riser” cable which is designed for permanent installation in non-moving situations. As @mordiev experienced, solid core wire will fatigue and break over time due to movement.
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:cthulu:I have been an electronics technician since 1978. NEVER use solid-core wire, or cables made up of solid-core copper wires, like Cat5, Cat5E, Cat6, etc where the wires will be flexing, bending, rolling around and just moving. Take an old metal coat-hanger wire or bailing wire or any solid-core wire, (not just copper)… bend it over and over at the same point and it breaks. ALWAYS use stranded wire, or cables made with stranded wire, for any application that requires the wire and/or cable to flex frequently. Solid-core wires, and cables made from solid core wires, are for things like AC power wiring or in applications where the wire/cable will not move once installed. Hard-break. End of discussion.
Also, the more strands and smaller diameter of each strand, the more flexible the “Wire”, or more accurately “Cable”, is.
For example, look at welding cables. Each of the two wires/cables are made up of small diameter, multi-stranded copper wire cables. I say cables because it is a bunch of small-diameter coper wires bundled together and twisted together like a rope and all of those tiny diameter wires touch each other.
That makes those cables last long, deliver a high amount of current to the job, and can bend over and over.
Just my 2 pennies here, I would use SHEILDED 18 gauge cable from Belden or a similar company. Especially to the motors. 22 gauge wire found in flat ribbon cables is too small to deliver the amount of current need to drive the stepper motors.
Also, always ground the shield wire, but only on one end of the cable. The shield wire is usually grounded at the controller or at the motor driver. The shield surrounds all the wires inside the cable in a “tube” of sorts and helps prevent motor “noise” from bleeding out. It provides a path for that electrostatic “noise” to go to ground and, thus, not interfere with the timing of the microcontroller. HOWEVER, if that shield wire is grounded at both ends of the cable, you are introducing ground loops. Ground loops are bad. Just always terminate the shield wire of a shielded cable at one end.
Also, when dealing with motors from a stepper driver, it is best if they use an opto-isolator on the data lines. Since the data is always from the controller to the motor in one direction only, an opto-isolator allows the ones and zeroes to pass through to the motor driver, but the noise generated by the coils, through back-emf, etc of the motor do not feed back to the microcontroller, keeping the data signal clean.
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Well, FWIW, I’m using solid core CAT5 for a little of my switch wiring.
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It’s the switches, which are tolerant of becoming disconnected, in that they will simply register as triggered.
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I’m ONLY using a pair of wires to take the switch out to match the motor wiring length, and only for the second of each set of X and Y switches. These are the segments that go from the switch into the gantry tubes, so there should be no flex in these once they are set up and in place.
I used pairs from the CAT5 because it what was ready to hand when I was wiring up the Primo. So there are some parts that could use it reliably and safely, but for the whole run, not so much.
I kind of wish that I’d got the motors with the JST connectors on them so that I could run wires that had a minimum of extra connections on them, but those just aren’t the motors that I bought. I’ve got those connectors out of harm’s way at least now.
This is the real key here. I think solid 22 is fine for this application as long as the proper bend radius is always observed. The issue is that the tape measure trick does not ensure that for solid wire and a lot of the smaller cable chains do not as well.
If proper bend radius is observed the wire will not harden and break at a single point. The bend radius of stranded wires is smaller than that of the same sized solid wire.
This is why you can use stranded #6 wire in a moving application the same way you use stranded 18 awg. Even though the individual strands in a #6 wire are about as think as a solid 18awg.
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