Mesa thcad and mesa 7i76 physical connections

1. THCAD-10 has 10V maximum input so needs an external resistor for direct connection to the torch. (2.9 M for 300V full scale, 2.4M for 250V full scale)

2. Like rodw, I would recommend using the automation interface which will work directly
with the THCAD-10, especially if you are not familiar with plasma machines. as direct torch wiring needs to be done by a professional.

I studied Esab manuals and other manufacturer manuals as well. The arc voltage will be in the range of 400V DC, at least what I understood, I may be wrong also.

I am confused with the resistors.

What is the circuit diagram for THCAD-10 and without an automation interface??

I have a Thermel Dynamics A120 which is the 120 amp version of your machine (just a different color).
The A says it came  with the Automation interface (and SL-100 machine torch as standard.)

I strongly recommend you get the Automation interface fitted and probably buy a machine torch as well. The machine will sense if it has a machine torch or hand torch fitted and disable the torch triggering if it is a hand torch. The automation interface also solves the torch triggering and also provides an ArcOK signal. Whilst it is possible to synthesise the AcOK signal its not as robust as the signal on the machine despite what other members may tell you. You are talking 100 amps here, not some 30 amp or 40 amp pretender. Its a serious high quality machine, don't do it half baked!

And yes, the machine will go over 300 volts on piercing but 300 amps (eg 30:1 divider) is fine for the machine as we don't care about the voltage on piercing and the THCAD can handle 500 volts anyway.

If Thcad10 is used in single mode, FOUT- to ENCA- is required or not?

THCAD 5V and GND if supplied from 5V smps, is it OK?

I have earth terminal in panel. Can SHIELD be connected to earth?

I would not use the THCAD in single ended mode if a differential input is available
(as it is on the 7I76))

It's best to power the THCAD from the 7I76's 5V encoder power connections
as this improves noise immunity.

Its generally better to terminate the SHIELD to the + input (usually= table/work ground)

And for the voltage divider resistance, it is in series to -IN of THCAD.

Am I correct?

Yes