Bed Coating Settings with Z-Probing and Z-Max Homing

tkramm

I have a setup with Z-Max homing and z-probing. I have set Z_PROBE_Z_OFFSET_MODE to 0.

When setting the coating height and after running G32 S2 the Z_MAX_LENGTH ist updated accordingly (actually the wrong way around), but does not have any effect on the print height.

If I set the coating height to 0.5mm the Z_MAX_LENGTH changes from e.g. 140.0 to 140.5
Am I missing something?

Repetier

In BedLeveling.cpp runZProbe we have this code:

#if Z_PROBE_Z_OFFSET_MODE == 1

distance += Printer::zBedOffset; // We measured including coating, so we

// need to add coating thickness!

#else

// homig will go Printer::zBedOffset in addition, so correct here as well

distance -= Printer::zBedOffset; // We measured including coating, so we

// need to subtract coating thickness!

#endif

Printer::zBedOffset is bed coating. So measunring distance to bed gets reduced by that value for at least G30 probes.

For G32 there is this extra rule:

#if Z_PROBE_Z_OFFSET_MODE == 1

currentZ -= Printer::zBedOffset;

#endif

so no change in that case. The computation is

float zall = Printer::runZProbe(false, false, 1, false);
...

if (s >= 1) {

float zMax = Printer::runZMaxProbe();

if (zMax == ILLEGAL_Z_PROBE) {

return false;

}

zall += zMax - ENDSTOP_Z_BACK_ON_HOME + plane.z(Printer::currentPosition[X_AXIS], Printer::currentPosition[Y_AXIS]) - plane.z(0, 0);

Printer::zLength = zall;

}

So from this I would say increasing coating to positive reduces z max/z length. This is for latest version - as there were many errrors regarding autoleveling in past, older versions might behave different.