Mesh Grid Compensation

Puppet172

@dc42
I will put it at 40 and then I will do another mesh bed and then post it

Puppet172

Nylkos

Did you set you Z by "Home Z" or do you adjust with a piece of paper and G92 Z0?

I might be wrong but if your home Z and your offset isn't setup, that could cause the issue if before running M92 you your whole M92 should be off.

I will explain, if you home with your probe and your 0 is really 3mm, you then home with a piece of trigger and fix the difference but that will cause that when you run M92 and your probe triggers, they will assume that your are always minimun 3mm off...

Puppet172

@nylkos
how do i set the offset?

dc42

What type of Z probe are you using?

Puppet172

@dc42
uxcell LJ12A3-4-Z/AX 3-Wire DC6-36V 300mA NPN NC 4mm Inductive Proximity Sensor Switch https://www.amazon.com/dp/B00S50O152/ref=cm_sw_r_cp_api_OUWEBb2TQTHR5

Phaedrux

You can find your trigger height with this

https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height

dc42

Please post your complete config.g, homeall.g and homez.g files, and tell us how you have connected the inductive sensor to the Duet.

Puppet172

@dc42
Sorry for the late response

0_1535219144684_homeall.g

0_1535219157439_config (2).g

0_1535219167488_homez (1).g

and the way i have it hooked up is its Positive and negative wires are hooked up to the 12v power supply because it needs at least 6 volts i think and then its other wire going to the z probe input.

dc42

I'm sorry for the delay in looking at this, things are hectic right now with new firmware development.

dc42

I'm sorry it has taken me so long to look at this. Does your printer still have this problem?

If so, then I can think of a these possible explanations:

The Z motor is consistently skipping steps when moving in one direction, but not when moving in the other direction. To test this, home the printer, position the nozzle at a known height above the bed, then send these commands:

G91 ; relative mode
G1 Z15 F100
G1 Z-15 F100
G1 Z15 F100
G1 Z-15 F100
... (repeat that pair of commands several times)
G90 ; back to absolute

Then check whether the nozzle height above the bed is the same as when you started.

The print head is crashing into the bed before the Z probe triggers, causing missed steps at that point.
The sudden stop that occurs during bed probing is causing the missed steps. To check this, position the head over the bed but above the trigger height and send these two commands repeatedly:

G30 S-1
G1 Z10
G30 S-1
G1 Z10
...

The trigger height reported by the G30 S-1 command should remain the same to within about 0.02mm. Does it?

HTH David