After enabling Distortion Correction, Z moves with X and/or Y.

wfpaez

Hello,

I have a Due/RADDS converted PowerSpec Ultra printer.  I have configured the latest Repetier firmware to work with it perfectly.  I recently purchased an IR Z probe and have it mounted correctly.  In my configuration, I removed the right-most extruder and am only using the left extruder.  The z probe is behind the heater block, attached to the belt clip (I designed a belt clip with a mount) and is spaced correctly (the sensors are approximately 1mm above the plane of the nozzle).  I can perform the necessary low/high tests and am able to get a measurement of .5mm for trigger.  My IR probe is connected to Z-max.  There are end stops on X-max, Y-max and Z-min.

I have tried various dimensions for the z probe bed size, but they seem to be ignored.  My goal is to have NxN distortion correction for my bed via G33.  However, when I enable this feature and install the firmware, homing becomes erratic.  The bed would rise, hit the Z-min end stop, and then keep going - or, at least try.  I couldn't understand it, until I tried moving the head with G1 commands or Home X/Home Y via S3D.  Any command to move X or Y would *also* move Z.  So, if the bed was close to Z end stop, it would keep going, trigger the end stop, and continue to try to go through the end stop - because the other dimension (X or Y) hadn't hit its end stop.  

I moved the head to the middle of the printer, lowered the bed and tried moving X or Y by a small increment.  The bed would move with the G1 X/Y command.  I have even tried using another Z-probing section from another post, but the results are the same.  For the moment, I have reverted to the non-Z probing configuration.

Does this sound familiar to anyone?  Is there a thread similar to this?

Repetier

First z min endstop + z probe does not make sense. z probing means bed height varies over xy and fixed z min endstop means bed is level and at all places z min = 0 is the same. Only exception is having z min endstop = z probe then endstoping on home would consider the different z heights on homing (if you autoleveled before).

Next homing does not correct z while homing only in the above exception it will add corrections to z after z is measured and you MUST home xy before z - only these homing orders will work correctly.  But the exception gives some troubles as homing only works when starting from a height where z probe is not triggered. So best practice is to home to z max if you have z probe, plus it has some other advantage. Only disadvantage is homing takes a bit longer since you need to go to max z and then to z min for printing.

With auoleveling/distortion enabled it will move z while moving. That is the correction. SO when you enable it make sure you have measured first. Means G32 S2 should be run once and it then enables autoleveling.

G33 L0 shows the distortion ocrrection. You can delete/reset it so it does not add anything until you measure a new grid.