The last time I used the big CNC machine, it tried to kill me. So I shut it down, and there things sat for … 4 years?
The problem, I believe, is that the motor cables (I was using CAT5 Ethernet cable with DB-9 connectors at the ends) are unshielded, and so when I put them all together in a bundle (you want to keep your cables tidy with a robot that moves around quite a bit), there was some kind of cross-chatter that did unhealthy things.
I spent a long time, occasionally looking for shielded Ethernet cable, but eventually I ran across these cables, and they looked like they’d do the trick.
I measured the existing cables, and put in my order. The new cables showed up last week.
Before I could install them, I needed to check one last thing; whether I’d wired the motor connectors “straight through” or with some crazy other pin wiring, which would have required me to cut them and resolder.
This was one of those times where you look back at your 7-years-ago self and say “hope you did right by me today”. I looked up the manual for the motor controller (turns out the schematic is silkscreened onto the case anyway), and popped the motor connector open.
Perfect match. Big sigh of relief.
This means that the new cables are a drop-in replacement for the old ones, and so 10 minutes later, the machine had shiny new cables hooked up.
I decided to declare victory and walk away at this point, because the next step is booting up and doing a few powerup tests, and I want to make sure I understand what I’m doing again, so as not to fry anything.
Next step, read up and re-check the wiring, then boot the machine up and see if the new cables fixed the problem!
It feels good to have finally made an attempt at moving this forward again.