Setting delta height

[Bustable]

i havent used my Delta for a while with duet and now im trying to use it again, the bed is all out of whack.
using smart effector

running the bed calibration and now it seems to have thrown the Z height out. it thinks it is 2-3mm lower than it actually is. if i go to 0 it grinds the belts.

how can i reset this, i cant seem to see it in the duet doco

[dc42]

Do you mean that after running auto calibration it thinks the effector is 2-3 mm lower than it actually is? If so then it sounds like the Z probe trigger height is incorrect in your G31 command. For the Smart Effector it should be about -0.1mm.

[Bustable]

this is my G31 command
G31 P100 X0 Y0 Z-0.1 0_1533473644711_config.g

this is what the calibration comes up with, this time, it varies between times.

[dc42]

Looks like the homed height (H parameter in M665 command) is a long way off the true value. Running auto calibration (G32) should establish the correct figure, if it succeeds. Did you run G32 delta auto calibration before you generated that height map? If so, did it succeed, and what deviation did it report?

Perhaps you should work through https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer#Section_Auto_calibration.