Z probe doesn't work

Joseph Schroeder wrote:

I built and set up a z probe plate per the instructions in Instructions - How To Make And Set Up A Z-Probe On The M4.
It almost works, but I get an error when the probing routine tries to retract, throwing a “NaN” error for the z retract distance. That value is set in the configuration.

Can someone tell me where that number comes from in the actual code?

My probe settings were 50, 60, 10 and 0.7 for max travel, feed rate, retract distance, and plate thickness. After consideration, I changed the plate thickness to 0 - bottom of sled, but get the same result.

Here is my log:

G38.2 Z-50 F60 P0.1

[PRB:0.401,186.810,30.600,1.616,0.000:1]
$J=G90 G21 F1000 ZNaN
[MSG:INFO: Probe offset applied:]
ok
ERROR:2
Missing the expected G-code word value or numeric value format is not valid.

I think I ran into a similar problem where it doesn’t accept 0 as the plate
thickness, try setting it to 0.1 or something like that.

David Lang