THC CAD FOR PLASMA CUTTING

Hii,
I have designed a CNC Plasma cutting machine with Linux EMC2 as the CNC software. I hae purchased the Mesa cards, 5i25 and 7i77 boards. My question here is shule I also buy the THCCAD boards for the Torch height control.
I have an ESAB Cutmaster 100 series Plasma cutter with an automation kit included. Meaning that the divided torch voltage will be available fro this pre installed board from Esab. This divided voltage would be in the range of anolog 0- 10 volts.
In such a scenario can i input this voltage to the relevant pin in the 7i77 and use this to control the torch height. Please let me have your suggestion, because I want to finish this project asap and do not have the time to order and buy the THC CAD card from Mesa.
Kindly explain if this is possible

Yes you need the THCAD-10 card and I ship every day from my store .

JT

CNCLINUXSREE wrote: I have an ESAB Cutmaster 100 series Plasma cutter with an automation kit included. Meaning that the divided torch voltage will be available fro this pre installed board from Esab. This divided voltage would be in the range of anolog 0- 10 volts.
In such a scenario can i input this voltage to the relevant pin in the 7i77 and use this to control the torch height.

In theory, yes. The 7i77 has analogue voltage measurement on the inputs, but they may not be accurate enough:

From the manual:
"ANALOG INPUTS
All field input pins are capable of reading the input voltage. These are not highly
accurate or high resolution but can be useful for things like potentiometer inputs. Input
resolution is 8 bits and input full scale value is 36.3V. Accuracy is +-5%"

So, you will gave an analogue voltage that gives 70 discrete values between 0V and 10V. That might well be enough for THC, I am not sure how strong a function of torch height the voltage is.
If you need better resolution then the THCAD10 is probably the cheapest solution, and may add a useful degree of isolation.

andypugh wrote: So, you will gave an analogue voltage that gives 70 discrete values between 0V and 10V. That might well be enough for THC, I am not sure how strong a function of torch height the voltage is.

That would only give you a 4.3v resolution which is much too coarse (tip voltage 0-300v). You need to control the tip voltage to +- 1~2v to have quality cuts. He would be better off just setting the cut height and cut away like I did for quite some time until PCW invented the THCAD.

JT

Thanks for the quick answer. It was not the cost of the THC CAD which was a concern. It was the time that Mesa electronics takes to ship out this board to India. This is the problem. However when you say that it would give me better results, I shall order 1 THC CAD 10 immediately. But can you let me know if any other company could deliver faster. I could order bthe same on line.

Thanks a lot
SREEDHAR R

I don't know of any. Orders placed before 8am Central time ship that same day and by ship the packages are on their way to the USPS distribution center. For orders that qualify, International First Class arrives the same time as Priority...

JT

HII,
As suggested I have ordered a Mesa THCAD 10. Can you suggest how this is connected to 7i77.
The other end of this is of course connected to the Esab Plasma head. I shall come back with more details and question.

I don't see any orders for THCAD cards, you must have ordered from someone else.

JT

Dear John,
I ordered the THCAD on Mesa Electronics stores.
Can I order this with you also. I didnt know his. Please let me know if this is possible.

Sure you can order from me at mesaus.com

JT