THCAD 10 to Herocut 55i (1:1)

If the required resistance was 4.9 M, you would need to deduct 240k (0.24M) from that number when selecting resistors (because its already in the circuit)
But you should be working on a full scale of say 200 v for that machine
(200v -10v)/100 = 1.9 M
so 1.9 M total - 0.24 M = 1.66m
SO 0.83m per side (830k)

Leave it as is with two 1MOhm resistors, just adjust the scaling to something nearly valid.
It is not important at all to chase all this math, set the scaling to what the calculator says, start using the machine, check the voltage and if it differs a lot from what the manual says, adjust a bit scaling up or down.

tommylight wrote:

Leave it as is with two 1MOhm resistors, just adjust the scaling to something nearly valid.
It is not important at all to chase all this math, set the scaling to what the calculator says, start using the machine, check the voltage and if it differs a lot from what the manual says, adjust a bit scaling up or down.

Which was my original suggestion to try first. I think the full scale becomes 224 volts but check my maths.

Hi and thanks! I wanted to double check so I don’t burn anything down
So leaving the resistor and not adding any additional resistance will not make the card to get to much current (100ma).

Thanks all for the patience and I really appreciate the time and effort you give me. I find this to be so exciting:)

hi! I have now tried to connect and run my plasma, but I can’t get the arc voltage to display on screen. I have tried to connect as the first image, and have made the configuration as the picture. The output voltage is around 100V after the resistors. Do I monitor the wrong port? I have tried with all frequency settings and still no luck. How do I go forward?I read the manual that I green light should be on the Thcad board but one is blinking orange and one is steady glowing orange. The one that is blinking is blinking faster when arc is on 

 

Ekholm wrote:

I read the manual that I green light should be on the Thcad board but one is blinking orange and one is steady glowing orange. The one that is blinking is blinking faster when arc is on 

That is perfectly OK, so the issue is on the other side from THCAD to 7i96 or in the config, so check the connections.hal file for :

It worked! Now to the next problem. Now i was going to check the output voltage and adjust the TCAD voltage. But i only got 6.8V with the THCAD connected. When i removed the card i got 130V. Is the resistors to big or what is happening?!

I would say 6.8 is fine if you have thcad 10 10 volts is the limit. are you talking about the thc input or volt display?

6.8V at the THCAD input at 130 Plasma volts sounds
about right since the THCAD full scale input of 10V means that
you would have a full scale plasma voltage range of 191V