bearer ,
thank you for the prompt confirmation. I went ahead after receiving your reply and it all works
In case anybody refers to this thread:
On JohnSL board Signal pin is connected to Z_Probe_In pin on Duet
On John SL board +/- pin is connected to +3.3V on Duet
On JohnSL board -/+ pin is connected to GND on Duet
and in the config .g file for my delta printer is the following
M558 P5 X0 Y0 Z0 H5 I1
P5 and I1 being the important varaiables
Thanks again