Guidance with Interrupts

[Wellington]

Hi!

I have been using a Duet within a pick and place machine. It has been absolutely wonderful so far.
The pickup axis (V) has a limit switch at the top for homing. It then uses a digital flow switch to generate a signal when the flow drops, indicating it has picked up a component.
It also has an emergency switch in case the flow sensor isn't set up properly, to stop it going too far.

Currently, the previous version of the system uses a ghost axis to home, an endstop for the flow switch, and an interrupt with M581 T0 to stop everything if it goes too far.

It would be nice for the process not to be bricked each time, as the operator would have to recover it. A pause or a repeated action would be more handy.

I've seen talk about M25 and high segmentation, but have never been able to get it to work.
As for the input, I can likely choose whether to use an SD card, or serial. I gather this matters.

If there's any solutions that jump out, I would love to hear them.

If I've missed anything key, let me know. I'm very new to forums in general.

Thanks!

[T3P3Tony]

@Wellington do I understand the requirement is to have a very fast acting pause command, when a backup switch is triggered? Currently you are e-stopping the controller with a trigger when this backup limit switch is triggered?

[dc42]

@Wellington the best solution we can offer right now is to use M581 T1 to trigger a pause instead of an emergency stop, and if the time to pause is too long then enable segmentation using M669.

In firmware 3.6 we plan to support a CNC feature called Feed Hold, which I think would meet your requirement.