Topics created by hekav

@hekav said in BLTouch only works once on a Duet 3 MB6HC:

Is it possible that the long path of wires of the BLTouch an extruder in parallel influences the IO behavior of the Duet3 board?

I'm glad you found the problem. Yes, that is entirely possible. Stepper motor cables induce voltages capacitively to any nearby cables, especially high-impedance signals such as BLTouch in its default open-drain mode. So if you need to route stepper motor wires next to any other cables other than heater or fan power wires, it's best to use shielded cable for the stepper motor cable - ideally, 2 twisted pairs inside a shield. Alternatively, use shielded cable for the signal wires.

Workarounds that may have worked with your original wiring include:

Send BLTouch the command to output a 5V signal instead of operating in open drain mode Add a pullup resistor of e.g. 3K3 between the BLTouch output and +3.3V Add a capacitor of e.g. 10nF between the BLTouch output and ground (although that would delay the signal a little)