Hi Everyone,

I have a project coming up that I thought would be worthwhile documenting. I have a well-used CNT cnc router that I am going to re-wire from the computer cabinet to the servo drive cabinet on the back of the gantry for all the motor signals, limit switches, etc. I plan on moving from a massive 50ish wire cable with a mil-spec connector to a group of shielded Ethernet cables, color coded for each axis. I plan on adding a second wire carrier chain on the side of the machine that has none to keep the data cables well away from the power cables that run approx 25 feet from the cabinet to the same servo driver box (though straight through for the spindle power)

The reasons for this are because of errors that I have had in the past in that a faulty spindle cooling fan power wire (220v single phase I think, will have to change that too) caused extra steps to be added along the way from the computer based control (WINCNC) and the servo drives, which are then closed loop after that point.

And, although I "solved" the problem (after 2 years of ghost movements), I have realized that servos are best with the control getting the encoder signal back and second best with the shortest wiring of the control>drive open loop section and the longest wiring within the closed loop from the drive to the motor. Score one for chinese machines, they are generally made this way, although typical syntec controller is still "blind" to problems after the steps are sent out. Third best, my goal, is to have keep the drives on the machine, but have the data cables spatially separated from the power cables so as to minimize interference, and make sure the cables are properly grounded, ie the shielding is grounded on the control cabinet side only. Right now I have power and data together and I don't think the shielding is properly grounded.

I could try to just fix the grounding, but the machine is 15 years old and if the one wire has failed, that's probably a sign. The ethernet will allow me to make the cable more modular, and allow a move to a true closed loop controller (kflop / linuxcnc) if I still need too, but this is the "only fix what's broken" path right now.

So, I have ordered the molex connectors (plugs, pins, crimper, etc) to interface with the old stuff (and hopefully can move back to existing in minutes if needed while testing), color coded modular ethernet jacks, color coded shielded patch cables, and cable chain.

I'll try to take some photos of the existing setup and point out the problem areas, as it's not just my machine with a similar setup.