Configuring continuous rotation until an input pulls low

[jwilo]

If I wanted to control something like a PCB conveyor motor using Duet, how would I go about doing it?

From a high level, the control approach would be to start the conveyor stepper rotating, and continue until a light gate is broken and pulls a digital input low.

That sounds like an endstop, but it's not really, that light gate would typically be for example the light gate in the middle of a machine.

I would then want to start running the conveyor again, but that light gate would be pulling the input down still until the board that triggered it passes by.

Then I would want the conveyor to stop again when it triggers a second light gate at the end of the conveyor.

This would be trivial with a PLC or custom hardware and firmware, and I'm sure it probably is too, but I'm not sure how to go about configuring it.

Essentially, I'd like to run said axis I'm velocity control mode, rather than position control.

[o_lampe]

@jwilo IIRC you can set the external triggers in RRF to react to rising or falling edge only. It would then ignore the fact that the light gate is still blocked.

[achrn]

Redefine your endstops on the fly?

Could you set up the 'endstop' for the axis being beam A breaking, run until the endstop triggers, then redefine the endstop for the axis to be beam B breaking and run until the endstop triggers.