probe ground-PMDX 122-probe ground

[johnnydoughey]

I am attaching a probe on my PMDX 122 attached router... using J5=15 pin to send the signal.  I was given a schematic which showed using the J6 ground.  Is there any specific reason this should be used?  One of the posts I read stated any ground would suffice, but I do already have  an e-stop grounded on the J6 connection.  My J5 ground is unused, though.  Is there any reason this ground should be avoided?  I am new to electronics, but decades ago I learned in the world of 240 and 480 volts, any ground is perfectly okay.
Thanks much for the help...

[Steve Stallings]

All of the GNDs on the PMDX-122 connectors are electrically the same signal
and it will not matter which one you use. The COM on J1 through J4 are NOT
the same as GND and should not be used for this purpose.

The input signal to Pin15 should be your touch plate, assuming you are
intending to do tool length touch-off.

The GND should be connected to the cutting tool being measured using a
clip lead. Sometimes the frame ground of the machine may work, but in
general that is less dependable.

[johnnydoughey]

thanks, steve..I will recheck my leads.  when I do a diagnostic, the digital light comes on, but it also kicks the e-stop button on Mach 3.  I will reverse the leads and try again.

[Steve Stallings]

It sounds like you have something strange in your configuration. Please
double check your pin assignment for E-Stop into Mach3. If nothing seems
wrong there, please send us a copy of your XML file to look over.