Stop on hitting Z-limit switch while retracting?

[neilferreri (Neil Ferreri Ω)]

@DAH

soft limits cover this?

Yes.

@Julien

soft limits in GRBL params are only about the MAX travel, so I would think that GRBL does not care if you try and send the axis to some positive Z absolute value (i.e. go “above” the Z switch level).

Soft limits should work on either end of travel. They will prevent crashes on retracts, if enabled.

Limit switches while operating?

In addition to what Mike said, in your grbl settings $20 enables / disables “soft limits”. So, $20 = 1 will enable soft limits that won’t allow you to jog past the limits of your machine. This is assuming your machine is homed, your max travel settings ($130, $131, $132) and steps/mm ($100, $101, $102) are accurate, and there are no mechanical issues. No harm in enabling the soft limits if the other settings are accurate. The controller will enter a feed hold state and then alarm as soon as i…