New Project with Mesa 7I96 and THCAD-05

I checked yesterday that your ohmic sensing offset and scale was set correctly in  your custom.hal

See what happens if you jog the Z axis down until the torch touches the material. It should light up in the GUI

Sorry guys it seems my image was not clear enough. The top arrow with to point at Arc OK and the lower one was for Ohmic sensor indicators. Voltage display not a worry as I did see the expected volts with the 9 volt battery attached. I did have the ohmic box lit when I was trying to get an indication. And it did not show in Hal Show. I am using a micro switch in place of the torch tip and metal surface, switch closed = tip on metal. There is box on the parameters page that is for ohmic offset, that is what I thought needed a value in place of the 00.0 that is in there now.
 

Also, I was wrong. If you jog down so the torch is touching the material and then click the ohmic test button, the ohmic led in the GUI will light up. 
If it doesn't monitor ohmicsense.ohmic-on in halshow while doing that and see if it lights up.
Id that does come on Phill needs to tell you how to contact that pin in Plasmac so it is seen.

Ah yes the experts explain where I have been assuming the wrong operation. I thought is acted just like a home or limit switch. It does act like that in Mach or UCCNC. I will check that in the morning.

Ok I had a few minutes out in the shop I have a switch acting like the torch touching the metal. When closing the switch and clicking on the Ohmic test the Ohmic light does not come on. I do have Ohmic button enabled. When I push the Probe test button the Z moves down about 2" stops backs up and small amount sets the DRO to 0.1200 then backs up again and stops and sets the DRO to 0.00. If I push the switch it does nothing, just completes the movements above. I checked the circuit and the +24 volt supply and all looks as it should.
I did go through the homing sequence before doing any of the above actions.

Looking to find something I checked the input to the THCAD-5 with the switch closed shows about 19.4 volts. Looking at the write up for the Ohmic circuit attached below. the values for my board are in the file. I don't know if this is something but the voltage divider in my file is 4.9 and the write up show 32??