Setting the Z-axis Offset

With the autolevel installed, the Z-axis offset is important to set correctly.  It took me a while to figure out what that parameter meant.  Now that I have got it figured out, I'll write it to my blog to  make sure I always remember it.

The Z-axis offset is the Z-coordinate that will be loaded in the controller when the axis is homed.  That means, when my auto-leveler detects a home condition, the Z-axis offset should be the distance between the bed and the nozzle.

This can be measured with feeler gages.  It can also be measured by setting a high Z offset, then manually lowering the Z-axis until the nozzle reaches the bed.  The difference between the original offset and the Z-coordinate when the nozzle touches the bed is the Z offset.

You can also get close, then make fine adjustments.  If your first layer shows that the nozzle is too high, raise the Z-axis offset.  If your first layer shows that the nozzle is too low, lower the Z-axis offset.

To adjust the Z-axis offset in the Marlin firmware, go to Control/Motion/Z offset.  Use the up and down buttons to raise and lower the offset.

Once you get an offset you like, be sure to go to ControlStore Memory to save the settings in permanent memory so they'll be there after you power down your system.

Note: I have found out how to set the Z axis offset in G Code.

Use M851 Z<negative of Z axis offset>

Use M500 to store the current offset to firmware

Use M501 to load the current offset (and other settings) from firmware.

My Tronxy has a Z offset of about 4.9 mm.