Tried a mesh compensation with a piece of paper, disastrous results, here's a picture:

@Phaedrux hey thanks for the reply!
So here is the start Gcode we are using for every prints:

G28 ;Home all axis
T1
G1 Z10
G92 E0 ; set position
G1 X140 Y85; set nozzle position at the center
G30 ; zdatum
G29 S1 ; load bed mesh
G28 ;
G1 Z0.4
G1 X51 Y42.5 F4800 ; move to start
G1 X51 Y117.5 E7.0158 F1800 ; print line
G1 X51.675 Y117.5 F4800 ; move to start
G1 X51.675 Y42.5 E7.0158 F1800 ; print line
G1 E-1.5 F2700 ; retract
G4 P1000
M572 D1 S0.15

M117 NG printing..

Here you can find the homeall.g file:
homeall.g

And those are the pictures of the bed installed on the machine:

here is a picture of the IR probe mounted:

The bed is illuminated with a common led strip and we are using fluorescent tubes for illuminating the room.

Thanks for the info with the microstepping I'll tweek the values asap.

For the z datum we do include a single probe on the center of the bed during the start gcode but it doesn't stop when the nozzle touches the bed but as soon as the probe triggers which is a few millimiters before the nozzle tip.

Thank you again for your time!

Hi, thanks for the answer, so here is the firmware version:

and this is the heatmap I just got:

We are using the normal black buildtack and there is no writings or text or white lines. The only variation are the markings left by the older prints. Anyway the surface is like two weeks old.

We do run G29 after homing z and, before every print, we set the z datum then home, and then print (with G29 S1).
The heatmap does load for sure because i can feel the Z stepper moving througout the entire printing process.
It seems like it misreads the heatmap and lower when it shouldent and rises again when it is not supposed to.
What is the correct point to measure the x and y offset from the nozzle? Is there a marking on the IR board I should reference for measuring it?

I will also post the config.g below
config (1).g

We are also very confused about the z datum, what is it precisely? How do we store it correctly in the firmware? Looks like a simple single z probe an thats it, maybe we are missing something about it.

PS. We did follow the guides step by step for the set up of the IR probe.

Thank you for your time

Hi everyone! Me and my buddy modified a Sharebot NG printer and we are running Duet2 electronics .
Lately we decided to install the IR probe with a custom mount designed by me.
We are running a 91 point mesh using G29 command. We calculated the Z offset and got a 2.76.
The problem is that it seems the mesh is not correctly working. The first layer is very inconsistent , we get part of the print too close to the bed and part of the print too high .
We measured the probe offset but we have no idea how to do it correctly. how do you mesure it? where is the actual focal point of the probe so we can set the correct offset from the nozzle?
Another thing is the fact that the mesh is very inconsistent, we have a lot of devation even tho the bed is pretty flat. We are using the magnetic Build Tak kit (black version) is it good?
Then we are scratching hour had with the z datum, what is it' we are runnung it before G29 and again befor the G29 S1 in start gcode. Is it correct?

Thanks in advance.

Looks like the same error I have, I will check the probe offset right now.