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Hola tengo varias dudas.
mesa 7i96s, thcad 2, plasma stamos 125h cnc, linux cnc, qtplasmac.

El plasma tiene 2 pines que ivan al gatillo de la antorcha y otros 2 que son el arc volt.

Pa primera duda es si puedo usar los pinos del gatillo para encender antorcha ( por lo que e visto por el foro si con un rele de estado sólido ) lo medí i salen 10v mi duda es como tengo que cablearlo. ¿E visto estos reles podrían valer?

La segunda es que no me sale la configuración del thcad en pncconf pero e visto algunas personas que lo tienen.

Y tercera cual es la manera adecuada para la conexión a tierra tengo cables blindados. 

Puedo mandar fotos de lo que tengo si es necesario 

Gracias soy muy nuevo

Hola a todos soy muy novato en esto pero lo intento.
Monte un  plasma cnc con mesa 7i97s que consequi hacer que funcione bien hasta que le puse el thcad2, le hice solo 3 pruebas de antorcha y los motores ya no se mueven, save alguien si puede ser que se haya quemado la tarjeta 7i96. Se conecta a linux puedo encender antorcha pero no se como verificar cual puede ser el problema, gracias.

Mesa 7i95T or 7i97T would be all in one, but price might be on the high side for what you need.
You can safely use just a Mesa 7i92T, but must be careful with wiring as the pins are sensitive.
Having said that, i have Mesa 7i92 wired on several of my plasma machines, meaning very high interference environment, and the THCAD is wired with 5-7 meters if cable directly to Mesa 7i92 input, yet i never have issues, ever.
This does imply proper shielding and grounding is a must.
In your case just having good shielded cables and grounding the shield only on the Mesa side inside the box should be fine.

ARCOK is derived from THCAD. My unit has arc ok output but the relay on the inverter board is not working so I'm using mode 0 for now. ark-ok-low is 60 and ark-ok-high is 200. Pilot voltage seems to be around 157 so maybe I could set ark-ok-high to 145 or 150. I've been testing on a scrap piece of 1/2" I had so not sure if the pilot voltage changes based on material thickness.

Is ARCOK signal wired to plasma or derived from THCAD?

I have the THCAD2 setup for 10V range and 32 divider with the plasma divider set to 20:1 and the arc voltage is displaying correctly after I set the scale and offset. The Thermal Dynamics has a 15V arc voltage before the start is initiated and it is showing correctly along with arc voltage during pierce and cut. For some reason I can't seem to get the Arc OK input to work. I have pin 12 of CPC connected to +24V, pin 14 to Mesa input 15, and -24V connected to Mesa common for the input. If I disconnect the CPC cable from the plasma cutter and short pins 12 and 14 the Mesa input goes high so the cabling should be good.

I have noticed there is a 2 second delay after start is triggered before the pilot arc lights so by setting my pierce time to (2 + pierce delay) and setting "Ignore OK" I have been able to get it to cut and the arc voltage is right around 137 that the cut table shows for the material I'm using.

The service manual for the plasma unit shows that it has an "OK to Move" LED inside the case so I may have to pull the cover and check that as well.

Any other ideas what I could be missing?

EDIT:  I disconnected pins 12 and 14 from the control and checked across them while cutting and there is no continuity so it looks like I will need to pull the case on the plasma unit and check the LED.

FINAL EDIT:  I went through all the resistance and diode checks in the service manual and verified continuity of the relay pins and the "Ok to Move" LED on the inverter board lights but the relay does not close.  So the relay is bad.  I switched to mode 0 in QTPlasmac and that works ok.  Maybe some day I'll pull the inverter board and see if I can just replace the relay but the Mesa/LinuxCNC side is working fine.

I have never had issues mounting the THCAD inside the control box. The plasma has a CNC interface connector so its designed for this.
You will not have issues.

Saw this old iron while entertaining the machinery buying itch today on Kijiji -- www.kijiji.ca/v-other-business-industria...i-hit-18s/1716314528

That link will go dead with time, so for the record it looks like a Hyundai HIT 18S for $2k Canadian, not working. Seller says it has some repaired drives. I probably need to ask more questions, just not sure what all the right ones are.

Seller might be asking too much, but says he's open to offers. Any thoughts from more experienced heads here, whether or not something like this is worth a look and a retrofit? Or should I be running the other way fast as I can? I don't have any impressions, good or bad, about Hyundai quality, and I'm not sure what dead machines should generally go for.

On the scale of difficulty for retrofits, where does a machine like this fall? I'm no expert with HAL but have dabbled a little. Built my own plasma table with 7i76e and a couple THCAD's by riding on the shoulders of giants on this forum.

Thanks in advance for any time you spend looking at this.

Is it still recommended to mount the THCAD on the outside of the plasma power unit when the power unit has a voltage divider? I was thinking it wouldn't make much difference since the start and ok to move are coming directly into the electronics box.

50:1 would be OK with with thcad 5 volt scale.
on 10v scale, Use 20:1 which is 200 volt full scale. That will be more accurate. It will probably go off that scale briefly when piercing but  it won't matter as we don't care about the voltage until it settles back to cut voltage of about 130 volts. The THCAD can handle the over voltage.

You don't need a relay as your card has 2 amp relays built in to the high current outputs, Use one for the torch on. Adding a relay would just add an additional failure point and add some lag into the signal.
I think your plasma has the same divider as the TD  A120 I had. In which case, use a 30:1 divider without any scaling resistors on the THCAD's 10 volt scale. If you do have a 20:1 divider (I didn't)  you could use that. set the frequency divider to 1/32 and scale the sticker frequency by the same amount when configuring qtplasmac
You do need to use a pull down resistor on the ArcOK input which is discussed in the QTP manual.

Hi,

I'm converting a Crossfire Pro to LinuxCNC using a Mesa 7i95t and THCAD2.  I have the automation interface card in the cutmaster 60i so it has the torch start/stop, voltage divider, ok to move, and ohmic sensing on the CPC connector.  I'm still waiting for the THCAD2 to come in but the wiring for it seems pretty straight forward.  I've attached the wiring diagram from the service manual and I'm not quite sure if I can just wire the start/stop directly to a 7i95t output or if I need to use a relay.  If I understand the qtplasmac docs I should be able to connect the ok to move directly to an input but may need a resistor if the current draw isn't enough.  I may hook up ohmic later but would I need another THCAD2 for it as well?

Thanks,

Kevin

Esaber wrote:

Right now the Z is moving up and down only when sensing the metal sheet and then when the cut is finished. And if the metal sheet is slightly curved the Z does not account for that and we end up with a welded torch tip !

It should see that and move the torch up. This is a sign you are not reading the torch voltage.

Assuming you are using a thcad, look at the encoder velocity in halshow while not cutting. Is it bouncing around near the 0 volt frequency. (/32) 

I guess if the amperage is too high for thin sheet metal, you may not see enough variation in voltage... Tommy will know more than m.

Looks like the /32 setting was the ticket. Between that and making the offset/scale changes, it appears my voltage readings are in order. Next step is getting the voltage/height adjustments in setup.

Do you happen to have any material libraries for the Everlast 82i? IIRC, you were using that before. I haven't been able to find anything reliable online yet.

THCAD/THCAD2 frequency divide by 1 will not work reliably
with default 7I96 encoder settings, so as rodw suggests:
use 1/32.