Dear Forum,

I am trying to find the center of a round cavity by using M675 and a Z-Probe (Precision Piezo).

It is configured like this:

M558 P1 C"!zprobe.in" H4 F220 T200            
G31 P520 X0 Y0 Z0    

My M675 command is:

M675 Y R4 P0 F600

This works very well in the minimum direction of the axis (the Z-Probe value is around 515 when idle). As soon as it probes the max direction of the cavity I am struggling to get a trigger bigger than 520.

I noticed that my Z-Probe value goes down to under 500 when hitting the round cavity in max direction.

I guess when the piezo disc is being squished when probing into the min direction (causing a Z-Probe value bigger than 520). When probing the max direction, then it seems that because the piezo disk has less pressure on it, thats why the Z-Probe value goes under 500.

Any idea what I can do about this? Ideally one could also specify a "min trigger value"...

Thank you kindly.

Matty