@whosrdaddy Awesome that worked a treat thanks!

It is a Core XY with a Duet 2 WIFI and the latest version of the firmware

Hi All,
I have a Duet WIFI connected to my Hypercube Evo and X and Y home perfectly.
I am using a NPN induction probe with the brown wire connected to VIN and the blue wire to ground next to it, I have a BAT43 diode connected to the output from the probe and that is connected to Z Probe IN as per the diagram in the connecting a Z probe guide. It triggers when the bed comes up & the probe value shows as 1000.

The problem is when I try to home Z I am getting this Error: M280: Invalid servo index 3 in M280 command.

Here are settings in the config.g
; Z-Probe
M574 Z1 S2
M558 P5 H5 I1 F120 T6000
G31 P500 X0 Y0 Z2.5
M557 X15:485 Y15:485 S20

If someone can shed some light on this for me it would be great.
I did try searching myself but all the info I could find seemed to be related to BLtouch probes.

TIA
Paul