Are you suspicious that your Auto-Leveling Probe (aka Z Probe) may be malfunctioning? Some users have seen the Z axis go upwards when they click home or when running the Auto Leveling Process (G29).
You can run a quick test by issuing the following commands in your software.
The read-back from your M119 command should be as follows:
- x_min: open
- y_min: open
- z_min: open
The term "open" indicates that the end stops or probe are not closed or "TRIGGERED". In the image below, you can see an example of each axis (X, Y, then Z) being homed. In this example, the M119 command is given after each axis is homed, reporting the axes being "TRIGGERED" one by one. If your commands look like this, the end stops, probe, and Printrboard are functional. If not, see the table below for further diagnosis.
To diagnose, power OFF your Printrbot. Swap the wiring for your Y STOP and Z STOP connections - plugging the Auto-Leveling Probe into Y-STOP and the Y end stop into Z-STOP.
After "swapping" your probe and Y end stop. Send the M119 command again. Activate each end stop by manually trigger each end stop by pushing each axis to its "home" position one by one. To home/trigger your Z axis, put something metal (screwdriver/pliers) near the tip of your Auto-Leveling Probe. NOTE: Physically push the axes. Do not use the "home" buttons on your software.
See the table below for diagnosis on which components may need replacing.