Z-Probe and auto-level on a Cartesian

mmoerman

Hi,

I have been trying to get Z-Probing and auto-leveling to work on a cartesian, but seem to be having a hard time.
I have a servo based probe with a simple switch a the end.
I have measured the Z-Probe height, and determined X and Y offset. I am able to Probe using G32 S2. But once that is done results don't seem to change in the least. Whether I set my Z_PROBE_HEIGHT to a higher or a lower number, when I print the distance of the nozzle to the bed is always the same.
Given this is a cartesian my Z axis moves down to the Z min end stop not the Z max end stop, I actually use the Z-Max end stop to trigger the Z probe.
In order to work the Z-Probe the start script for the probing is "G1 Z30\nM400\nM340 P0 S2000\nG4 P1000\nM340 P0 S0" basically move the head up on the Z axis so the servo arm can deploy and then deploy the arm. Does the fact that I bring up the Z axis in the script somehow change the probing results?
With this setup should I home X,Y,Z before running the probe, or only home  X and Y? Would that help?

Printer is a Prusa i3 type setup all end-stops are min end-stops with X axis inverted.
I use latest stable Repertier firmware 92.9.

What am I doing wrong?

mmoerman

Repetier

If you have z min endstop it does not use z probe height for homing. In fact it makes no sense to have a z min endstop and z probe. Use z max endstop + z probe or make z probe your z min endstop (requires dev version to work correctly). 

I always advice to have z max endstop (you can connect it to z min pin no problem). And don't say it takes so long to home. It gives you so much more freedom it is worth a few seconds more and if you z home after print finished it is even fast and does give access to printer. Compared to print duration this is neglectable but gives you much less pain.