How do we address a second probe?  Do we just use the command and change probe to probe1 for the second probe?

Thanks

You can refer to the Mill GCode Programming Manual page 19. G31, G31.1, G31.2, and G31.3.  
You use the same command only instead of G31 you will use G31.# depending on which input you mapped it to, Probe1, Probe2, or Probe3.

Perfect!  I was looking in the wrong place making it more difficult than needed!

Be aware that not all controllers currently support multiple probes, so be sure to test carefully.

Allan

Thanks my system looks good for more than 1 probe but still need to see if it works.

G31.1 does not work even though the BOB and ESS have pins connected correctly and the probe lights up on the board and in diagnostics.
It looks like only G31 really works in Mach4  You can have a second probe which is recognized but the probing routine does not work in a G31.1 move.
Guess I will use a switch to go between the 2 probes.  Why is it documented in the manual.  Even the #variables are not correct.  The manual says #5071
and #5071 are for probe1 (second probe) x and y position values but looking at the probing lua code done by Mach4 programmers, those variables
are actually G31 skip signal machine positions NOT G31.1 X and Y probe absolute positions.  Hours wasted to figure that out!

Looks like ESS plugin only supports one probe.  Wired second one to the same port (in parallel) and running G31 works fine with either probe.

Problem solved for now...

New ESS plugin now works for multiple probes!!  YES!!