G29 get a warning only if bed is heated

[cjccjj]

Hi, I newly setup a Z probe for my system running Maestro, which is an Inductive sensor.

; Z-Probe
M558 P5 C"!zprobe.in" H3 F120 T3600				; Z probe setup
G31 X-31 Y-0.7 Z1.050 							; Z height 1.050mm, X offset Y offset
M557 X10:190 Y7.5:142.5 S20:15                  ; define mesh grid

It all worked fine when the bed is cold

g29
100 points probed, min error -0.157, max error 0.018, mean -0.089, deviation 0.045
Height map saved to file 0:/sys/heightmap.csv

but when I run G29 while heating the bed to 60 degree, I get a notification of response time too long and a warning as below.

g29
Warning: the height map has a substantial Z offset. Suggest use Z-probe to establish Z=0 datum, then re-probe the mesh.
100 points probed, min error -0.140, max error -0.035, mean -0.076, deviation 0.019
Height map saved to file 0:/sys/heightmap.csv

The results seem fine despite the warning. Should I change anything about it?

[dc42]

@cjccjj to avoid that, before you do mesh probing using G29 S0, move the head to a few mm above bed centre and do a single G30 probe to re-establish Z=0. You can do this in file sys/mesh.g.

[cjccjj]

@dc42 Thank you for the quick reply, I believe that will solve the warning issue. But I am not quite sure about how to write the mesh.g file.

So in mesh.g, after moving the head and G30, I must use G29 with S parameter, otherwise, it will call itself again in a dead loop, is that so?

[jay_s_uk]

@cjccjj sort of. in mesh.g as you say you need the move, the G30 and then G29 S0.
If you don't have G29 S0 it'll just stop at that point and not do a mesh

[cjccjj]

@jay_s_uk Thank you. so this is the correct way to do it. It is just a bit strange to use G29 to call a script and run itself within it, so I was not so certain about it.

[jay_s_uk]

@cjccjj G29 will run mesh.g if its present to allow certain commands to always be ran before the mesh is created.
if mesh.g isn't present then G29 S0 is ran