[DartB]

Hello everyone,

My workplace has an Axiom router table and controller that was converted almost a year ago by a previous intern to be controlled via LinuxCNC through a CNC4PC C10 breakout board. After about 9 months of no issues, the limit switch outputs stopped working. That previous intern figured that the C10 board had just gone bad and bought a replacement, but after connecting it identically and powering on the stepper shuddered intensely for a few seconds before the second C10 board burned out completely. He tried a third board and saw the same results

He opened a support ticket with CNC4PC and Arturo recommended checking the system for connections or shorts that could cause ground loops. Shortly after this point, the intern was given other tasks to do before graduation instead of the router repair, and the task has now been given to me.

I went through the system and removed several connections that created continuity between terminals that Arturo said should not have any. To test the system, I connected the originally installed C10 board, which functioned normally outside of the limit switch issue. This board worked.

After doing that, I installed a fourth new C10 board. As soon as I powered the system on, the steppers started to shudder just like with the second and third C10 boards.

I continued talking to Arturo and he recommended checking the power consumption of the C10 board, which I did with the original installed again and found to be between 150 and 200 mA, well below the 400 mA max. I unfortunately can't repeat that test with the second, third, or fourth boards because they burn out after a few seconds and the output enable circuit stops working.

*TLDR: The original C10 breakout board runs mostly fine with only one issue, while three replacements have burned out within seconds.*

Does anyone have any idea what could be going on? Is it possible that the three replacement boards were faulty, or is it more likely that the original C10 is just more resistant to whatever the actual issue is? Do I need to check the grounds again?

Thank you in advance.

[atex57]

Does only one axis shudder or all?

[joeavaerage]

Hi,
you're going to have to spend some time to diagnose it.

Disconnect all drives and switches, and connect them up one by one.

My guess is that one of the drives is faulty and it back feeding inductive voltage pulses from one or more of the steppers, and that will fry the board.

Craig

[joeavaerage]

Hi,
the C10 is a bi-dircetional breakout board, and very basic. The input and output IC's are all low power CMOS operating at TTL levels, ie 5V. They are very tender to overvoltage, especaily inductive voltage spikes.
If you were designing your own you would incorporate over voltage protection into each circuit. You could do the same, a 4.7V Zener at each input would be a start.

I made my own breakout board to suit my mill, Mach4 and an ESS motion control. All its IO is 24V tolerant, while the driver outputs (6 axis) are all differential. Uncommitted outputs are 24V sourcing and sinking.

Craig