Secondary Tool move breaks Z homing

[optical]

@dc42 So the problem is indeed that the endstop wires runs in the same wire bundle as the motor. I have temporarly solved the issue with low pass filter with cut off frequency 1Khz.

I'm currently working on having expansion boards and D-Sub cables which should ease my assembly of the Pick and Place machine. I will address this issue in the new revision of the cableing.

I'm deeply sorry for my lousy cableing which caused so much trouble. I wasn't expecting this issue because both two steppers didn't caused the issue.

Thank you very much for helping me find the issue in my machine.

[dc42]

I'm glad you solved it! Bear n mind that the Duet 3 has 27K pullup resistors on the inputs, so any low pass filter you add should have a low enough resistance so as not to affect the low-level voltage significantly. A 1nF capacitor connected between the input pin and ground would probably be sufficient, but then the output transistor in the NPN sensor will discharge this rapidly when it turns on. That is unlikely to harm the sensor, but if you want to avoid it then I suggest a series resistor in the range 100R to 1K between the sensor output and the capacitor/IOx_IN pin.