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Great!
just one last silly question: how can i find out to what pins the encoder connects?

i can't find anything about the physical pin numbers in the .ini or .HAL file?
i connected the stepper drivers to wahtever the BOB said and that worked but i feel that this is just luck...
where can i find this?

A CNC4PC C10 (that the OP used) is probably a good choice as its an all 5V BOB.

should i get another bob? and if so what would you recommend?

Unfortunately it would be pretty awkward with those breakouts as the inputs
are slow 12V signals. Even with level shifting I don't know if they could deal
with the ~8KHz signals from the THCAD using the highest divider ratio (128)

The breakout board inputs are activated by grounding so you could try adding
a NPN transistor/small MOSFET to do the level translation from the THCADs ~5V signals
to the 12V required but no guarantees...

A better solution might be to drive the appropriate 7I92 line directly (with maybe a 100 ohm
series resistor for safety)

If you are going to do this (I wouldn't) Make sure your divider resistors are rated for the voltage
and the power. This is difficult as 25KV times 5 mA = 125 W! (this is assuming a THCAD2 jumpered for
5V input and an external 5M resistor)

You can get away with a smaller watt rating because of the "peaky" nature of the HF signal
and it's short duration, but I would not skimp on the voltage rating. I would use  (5x) of
something like this as a minimum:

www.digikey.com/en/products/detail/visha...0001004FAC00/1994729

Because the voltage spikes are mainly in the negative lead,, I would put 4 resistors in the negative lead
and 1 in the positive lead. This combination will (with THCAD2 set for 5V) give a full scale voltage of 255V
 

The proper way would be to wire it to the rectifier output, and use 2 of 1.5Mohm resistors on each wire.
To answer your question, yes HF start can kill the THCAD, but... i have a THCAD10 wired through 2 of 1Mohm resistors at the plasma plugs, plasma is China made Kzubr 60A, it is HF start, it is in use for over 6 months i think, it did not die, yet.
Do this at your own risk, it is not recommended but it works.
Use 2 resistors, 1 on each wire, this is very important, short wires from plasma to resistors, no more than 20-30cm, keep those wires and resistors at least 10cm appart or mount the THCAD close to the source.
And, torch is not positive on plasma, it is negative, the clamp is positive.

Hello!
I just bought a THCAD2 board.
As the manual says i have to connect a 2.9M resistor in series between INPUT+ and thorch. That's clear.
I have a parkside ppsk 40 a1 plasma cutter.

My question is where do I have to connect the Analog IN terminals, is it OK to connect to the cutter's output(torch and clamp terminals) or I have to search on the PCB for the rectifiers and solder wire after them?
I'm asking that becouse the cutter have HF ignition and i don't know does the board survive 25kV ignition voltage(I read that value somewhere on the forum).
Thank you!
 

Hi all,

i have a similar question, as above. I want to connect a THCAD to my 7i92.
On the 7i92 i run 2 breakoutboards (see below) however i can't figure out what pins  i need to connect the thcad to.
How can i find where the encoder pins are connected to?


www.amazon.nl/DollaTek-5-assige-CNC-brea...rivers/dp/B07PNDXZQK

Thanks!

Do you have the HT200 plasma?
It should have a divider, so try to find the service manual for it, Hypertherm had those always available on their website, but not anymore, now they want money for documents, but still not much, so at least they are not greedy.
Have you looked inside the HT200?
Get the THCAD5 if available, with added resistors it works with any divider or raw voltage.

Hey Tom good day to you, my names Tom as well BTW
(theres never enough Toms on the job! haha)
So THCAD5 would be for a divider board with a 0-5v range and thc10 would be for a divider board with a 0-10v range correct? So I will need to see what the voltage output of the divider board on my hypertherm is if there is one or purchase a divider board and wire it up to the raw arc voltage correct? I apologize for bugging you guys with so many questions but I really don't want to order the wrong components so it is very much appreciated.

The mode can be automatically selected based on voltage sensed. You know at startup its not cutting, start in hypersensing mode but if the voltage exceeds 24 volts, calibrate to THC range and stay there until it falls to say < 5 volts, go back to hypersensing mode.

Yes will need 2 factors one for the arc voltage and one for the Hypersensing, also the QtplasmaC need to change from THC to Hypersensing Mode.
 

I don't think the contractor is required as the hypersensing circuit is impervious to high voltage.
Currently when the voltage exceeds 24 volts, the component is seeing an arc voltage and it never breaks now. The thcad always sees a bit past the full scale and the 390k resistor sets full scale to 23.5 volts anyway.

So what if you mux the  THCAD calibration instead? once it is > 24 volts, recalibrate it to be fullscale 200 or 300 volts?

PhillC54.
This is an interesting aproach, basically we are muxing the THCAD input, may be some processing power can be saved using only one encoder.
I re-draw your schematic just to make it more readable, I think this will require some changes to PlasmaC componet.
 

What resistor value would you use between positive of the isolated power supply and the positive input of the THCAD ?