Thank you dc42, running probing with bed heated will result in failure because of the FSR pressure sensors, I think their resistance changes significantly with a temperature increase, what causes nozzle to smash into the printbed.

And as far making corrections to bed.g go, I think I will go that route.
The center of printbed is fine, it just when it goes away from the center everything gets messed up.
Homing repeatability is not too bad after all, it varies a tiny bit, but it is acceptable, it would be great to have live Z micro adjustment when the print starts.

Can you think of a macro that would probe only a center of the bed and set Z 0 before every print?

Thank you, now I ran into another problem.
I decided NOT to run auto calibration and stick with adjusting all parameters manually because my bed is not completely level and I cannot base my calibration if everything is off by a little bit, but I still want to use mesh bed compensation.
My printer uses FSR pressure sensors and the amount of force it takes to activate them varies with X Y coordinates, so the question is, if is there any way to compensate for the "dip" it takes to activate sensors when probing for mesh bed compensation.
Also what gcode would I use to only adjust the printer height, or set Z0 before printing, I don't think if I should rely on repeatability of my endstops atop my XYZ towers.

it seems just slowing down a little further away from bed when probing.
I changed the probing points to a little closer (10mm) to the center of the bed than they were originally and it worked.

Now I am trying to figure out how to adjust Z offset, so when the print starts, it is not diving into the bed.
I tried adjusting Z in the M558 command, is that right? And if yes, does increasing the number will result in the nozzle further away from the bed or it will bring it closer?

Hi folks!
After a while after giving up on trying to get my delta printer working I decided to go back and give it another fresh try.

So the problem I am experiencing is, that when I run Auto-Calibration, the nozzle touches only first 4 perimeter points and then fails to go all the way down to the bed and a message saying "z probe was not triggered during probing move" pops up on the screen.
Weird thing is that as the probing proceeds clockwise, it starts at 12, 2 o'clock 3 and 4 are fine but they rise as they go, you'd think that 11 o'clock would come back down as it comes close to 12, but it keeps rising.

I tried adjusting the homed height and when I increase it, the nozzle touches first 3 point no problem, but next few points it crushes into the bed and I turn the printer off to avoid any damage. When I increase the height, it touches first few points and then floats in the air.

As far as the endstop offsets go, I am right on money with a nozzle dead center between the 3 towers at a homed height, and it doesn't need any adjustments.
When I move the printhead close to the bed, in the center I am about the thickness of paper away from the bed, when move it away from the center, the nozzle hovers about 0.5mm higher (dishing effect).

following is a clip showing what is happening:
https://drive.google.com/file/d/0B5AUUqBo3lTET3RWbXVJMHBTTEE/view?usp=sharing

@dc42:

Most of those questions are answered at https://duet3d.com/wiki/Configuring_RepRapFirmware_for_a_Delta_printer.

Why do you want to auto calibrate without changing the endstop adjustments?

The reason is that there is no way for me to level the bed and the calibration assumes that the bed is perfectly level.
I just wanted one solid dimension that for sure is right in order to base calibrating process on it.
If everything is off by a little bit, then what good is the calibration?

Thanks a lot!
I dug a little deeper into Gcode on RepRap's wiki and got it sorted out!
I have other questions regarding this firmware and using it on a delta type printer, but there are so many of them that I don't know where to start…

Like, if I have set my own endstop offsets and i don't want the Auto calibration to change them, would it be possible to avoid changing endstop offsets during Auto Calibration?

Where do I apply tower rotation for delta? In Repetier they are saved in EEPROM as 90 , 210, 330.

Where do I apply diagonal rod length corrections for delta printers?

Where do I apply radius corrections for deltas?

I own this board for about two weeks and I am still trying to wrap my head around configuring it right. My previous board that ran repetier didn't have enough processing power to operate a delta type printer, hope this board will bail me out

Hi!
I need help using the newly introduced mesh bed compensation on my delta printer.

I am new to RepRap firmware and I am trying to get used to setting everything up using gcode .

I've read that to define the grid, I would need to use M557.
But where would I type the grid settings? would it be in a bed.g / config.g ? and also what would be the format of the grid?