Resuming after a door/alarm state resets M7 (Coolant) state

[amoineau]

Hello,

Context

We are developing a machine that can cut and mark textile.
In our configuration, we are using M7/M9 to command a relay thanks to the 'coolant' output. This allows us to direct the spindle signal to the primary or secondary tool, and thus change tool easily from the g-code.

Problem

Unfortunately we noticed that when a door sensor or our emergency button was triggered, GRBL would reset the 'coolant' state. In our case, it means that we revert to the default tool. So if we trigger a door signal mid-shape, we then resume with the wrong tool.

What we tried

In protocol.c, We commented the de-energizing of the coolant when going into sleep state (line 622). So now the coolant isn't reset when triggering a door, however, when sending the resume signal it resets a second time apparently.

What we need

We couldn't find a way to prevent this behaviour, could someone help us find a solution please.
We would like the coolant state to be unaltered by door/alarm/hold or any such signal, considering it only select the tool, it can't activate it.

Thank you in advance for your help.