Mesh Grid Compensation

Puppet172

@dc42
M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X80 Y80 Z2000 E100.1 ; Set steps per mm
M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000 Y6000 Z100 E1200 ; Set maximum speeds (mm/min)
M201 X500 Y20 Z350 E250 ; Set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30

dc42

Your Z acceleration in M201 looks very high for 2000 steps/mm. I suggest you reduce it to around 40. OTOH your Y acceleration looks very low for 80 steps/mm.

Puppet172

@dc42 I think you got my m92 and m201 mixed up because my m92 z is 2000 but my m202 isn’t

dc42

@puppet172, I was referring to your M201 Z350.

Puppet172

@dc42

What would you recommend putting it at ?

dc42

40, as I said before.

Puppet172

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

Puppet172

@dc42

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