Probe as external trigger

svp_vub

Hi,

I want to use a Z probe as an external trigger without defining it as an endstop (RRF3.3).

The z-axis on my project has several probes (4) with different uses. One of them is a touch down switch that can be used to probe an object height, but if triggered otherwise should shut off the machine for safety reasons.

I could make the trigger work correctly with this command combination:

M558 K0 P8 C"^io7.in" F500 H5 ; Define the Z probe
M574 Z1 S2 ; Define low Z endstop to Z probe
M581 T2 Z1; Trigger T2 on endstop of Z1

However this messes with the homing as it will now use the K0 probe to home Z. Is there a way to use a Z probe as an external trigger without having to use the endstop as middleman?

I was thinking of maybe defining "^io7.in" as an input pin with M950 J1 C"^io7.in", but I get "Error: M950: Pin 'io7.in' is not free", as it is already defined as a Z probe as it should be.

Phaedrux

If you want to use the same input as homing and a trigger, you just need to redefine it before you use it. So in the beginning of your homing file you would need to free up the pin again, and remap it as the probe, then at the end of the homing macro, free it again and remap it as the trigger.

svp_vub

@Phaedrux thanks!
I fixed it by turning off the trigger, and re-configuring the endstop before and after the homing sequences.

I guess there is no way to immediately use probe K3 for example as external trigger?

Phaedrux

It doesn't really make sense to use the probe configuration mechanism as a trigger. It's not the probe you want to use, it's the pin, and that's already reconfigurable.