[CitizenOfDreams]

I have X, Y and Z home switches wired in series and connected to a single parallel port pin. Here is what happens when I hit the "Ref" buttons in Mach3...
The X axis works as expected - goes left until the switch opens, then slowly crawls right until the switch closes.
But the Y axis only works as expected SOMETIMES. Most of the time it just goes one direction until the switch opens, then immediately stops. If I jog the Y axis away from the switch and hit the "Ref" button again, eventually it will reference properly. Sometimes it takes 5 or more attempts.
The Z axis works MOST of the time, although I think a few times it did the same as the Y axis.
What do you think is the problem? Contact bounce? Something else? All the switches seem to work properly when I push them by hand and watch the I/O status.

[CitizenOfDreams]

Answering my own question.

Apparently, cheap microswitches have some contact bounce when you press them slowly (160mm/min). Increasing homing speed to 800mm/min made the switches work properly.

[ger21]

Try adding some Debounce in General Config, if your using the parallel port.

[CitizenOfDreams]

Try adding some Debounce in General Config, if your using the parallel port.

I have tried that, but it didn't help.

[ger21]

What values did you try? Somewhere between 3000-5000 should help.

[CitizenOfDreams]

I don't remember the exact numbers, I believe I've tried debounce time up to 0.1 seconds or so (that would be 2500 in Mach3 settings).