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Using cat7 ethernet cable for signal wire to driver?

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  • Using cat7 ethernet cable for signal wire to driver?

    Is it a bad idea to use cat7 shielded cable to run the step/dir/com signals to my motor driver to the control card(Acorn)? It looks like my DB44 breakout might take a while to get here. That means me soldering wires to the male connector in tiny little tubes. I don't have any stranded wire that will fit inside the tubes. The cat7 solid copper wire fits perfect. I would have 6 wires to solder. I am not thrilled to have to solder these wires.
    Location: The Black Forest in Germany

    How to become a millionaire: Start out with 10 million and take up machining as a hobby!

  • #2
    Nah. It’s fine as long as it does not have to move.

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    • #3
      Danke! No it doesn't have to move. There are four pairs with individual shielding of the two wires that are twisted. Do you think it will make a difference which wires I actually use?
      Location: The Black Forest in Germany

      How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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      • #4
        Originally posted by Black Forest View Post
        Danke! No it doesn't have to move. There are four pairs with individual shielding of the two wires that are twisted. Do you think it will make a difference which wires I actually use?
        Nope
        Helder Ferreira
        Setubal, Portugal

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        • #5
          I edited this post.
          Last edited by Black Forest; 01-14-2022, 02:26 AM.
          Location: The Black Forest in Germany

          How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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          • #6
            No, it wont matter with single ended signals which I think you are using where one wire is a ground and the other is just a positive going signal in reference. Higher end controls will have differential outputs which handle noise and longer cable lengths better than single ended. If they were differential outputs then you would want to use the pairs for each differential output. A good way to tell if you have differential outputs is if there are 4 step/direction connections per axis. They might be labeled +step,-step,+dir,-dir or something like that. If step/dir share a single ground then they are single ended outputs.

            On my mill I used a single ended to differential IC to drive rj45 pairs for the cable that connects the 4th axis driver box for my mill. I tried using single ended but I was having a huge electrical noise issue and was losing and gaining steps between the control and the servo drive. Switched to differential and all my problems went away. With single ended connections when the pulse line is off it just floats, there is nothing that brings it low which means that electrical noise from the environment can be enough to trigger steps in the drive. With differential the polarity of the pulse wires is swapped so it is very difficult for noise to trigger a step response.

            Not sure if that made any sense.

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            • #7
              Originally posted by macona View Post
              No, it wont matter with single ended signals which I think you are using where one wire is a ground and the other is just a positive going signal in reference. Higher end controls will have differential outputs which handle noise and longer cable lengths better than single ended. If they were differential outputs then you would want to use the pairs for each differential output. A good way to tell if you have differential outputs is if there are 4 step/direction connections per axis. They might be labeled +step,-step,+dir,-dir or something like that. If step/dir share a single ground then they are single ended outputs.

              On my mill I used a single ended to differential IC to drive rj45 pairs for the cable that connects the 4th axis driver box for my mill. I tried using single ended but I was having a huge electrical noise issue and was losing and gaining steps between the control and the servo drive. Switched to differential and all my problems went away. With single ended connections when the pulse line is off it just floats, there is nothing that brings it low which means that electrical noise from the environment can be enough to trigger steps in the drive. With differential the polarity of the pulse wires is swapped so it is very difficult for noise to trigger a step response.

              Not sure if that made any sense.
              Made perfect sense!
              Location: The Black Forest in Germany

              How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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              • #8
                CAT8 would be even better. There is a least one vendor on Amazon using 23AWG in their CAT8 cables. Some CAT7 cables may be as small as 30AWG.

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                • #9
                  Sounds like it should work perfectly. Probably a case of a bit of overkill in terms of the actual specs. And as far as that movement thing, even that can be compensated for if you can be careful about how it is routed. After all, stranded wire is just a bundle of solid wires. It is a matter of controlling the amount of the bending relative to the wire's diameter.
                  Paul A.
                  SE Texas

                  And if you look REAL close at an analog signal,
                  You will find that it has discrete steps.

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