Currently having some issues with an AXBB + Clearpath servos (used previously UB300ETH + Clearpath with great success).
I have two servos hooked up to the AXBB and one of them has an intermittent “ENABLE” issue. Steps will be lost (servo is de-enabled) at random times, for a random amount of time (from a quick glitch to a few seconds). Only occurs on one servo, on the EN signal (STEP and DIR are unaffected).
On the UCCNC software side, the Diagnostics window shows a constant “EN” signal. On the Clearpath MSP software I can see that the servo input “Enable” is lost at the random times stated above.
On the hardware side the initial wiring was done according to the CNCdrive doc (all negative STEP/DIR/EN pins to 5V0 and the positive pins to the AXBB non-isolated terminals), I always measure a steady 4.730V at the EN pin, even when the servo loses the enable signal (power supply is set at 4,95V). When in series with the EN wire, I measure a steady 6-7mA, so it’s not a loose wire.
When I tried to probe the signal with a scope yesterday, I grounded the 5V0 pin to the scope’s ref and the 5V faulted on the AXBB (The EN pin started drawing 47mA when that happened). I unplugged everything and restarted and the problem went away, could not reproduce it. The issue came back today: tried to switch the control wires of both servos and the problem went away again. I then tried to switch the wiring to “sinking” (all positive STEP/DIR/EN pins to 5V+ and their negative counterparts to the AXBB terminals) and the problem is still there: intermittent enable state of the servo.
I am suspecting that I have the same issue then the fella here:
https://www.forum.cncdrive.com/viewtopic.php?f=4&t=2150
But the guy never came back with the fix he did…
I am tempted to simply ground the 5V0 rail to “earth” to make sure there are no floating references, but this was not recommended by CNCdrive (at least, not link 5V0 and 24V0 to keep the isolated outputs separate).
This setup drives an expensive and dangerous machine… I cannot afford to lose steps here and there and cause a crash. Any idea on where to go from here to fix this?