THCAD-10

Wasn’t sure if I should start a new thread or reply in this one, chose to reply to this as it closely resembles my situation.

I have read through the thread a number of times as well as the various man pages and Mesa documents. I am using the same components I.e Mesa 5i25-7i76-Thcad 10 on a gantry plasma. I orinally configured using pncconf, then RodW helped me to get my torch to start and the Arc Ok signal to work. As a result I have been able to cut items but as the steel warps my torch gets closer to the steel until it touches. As I have the thcad I would like to utilise it. I have installed the thc-pid component that JT uploaded in the thread and modified my hal, postgui hal and Ini files to reflect the thc details in the files uploaded by kb8wmc. I got the pyvcp screen ok and thc showed active as soon as the machine was enabled. When I tried to home all, which has always worked perfectly I could see z axis value changing on the dro but no action on the actual machine. I then tried to home my x axis which again has always worked and although that appeared to be working it ignored the home and limit switch and by the time i got it stopped had broken the switch and hit the hard stop. I have just finished re-aligning the z axis and fitting a new limit/home switch. I reverted back to the pncconf files and homing is working again. I realise that something I copied across obviously caused an issue but my level of knowledge at the moment is not telling my what. I have been constantly reading manuals for day now but am just tearing my hair out trying to get anywhere.
I am not interested in fancy screens and gauges or built in routines, is there a simple set of commands I can use to get the thcad to function and follow a requested voltage? I liked the look of the hal code uploaded by islander261 on page 2 of the thread but guess there is a lot more I would need to do before I could utilise it. Also I have tried connecting a battery to test the output of the thcad but it always reads zero. I am supposed to have the machine running a cut when testing this?
Or Is there a simpler thc that would be easier for me to use

Can you post your current hal and ini files?

As a basic hardware test, If you connect a 9V battery to a (powered) THCAD inputs, the yellow LED on the THCAD-10 should blink faster

Hi PCW

Thanks for the reply. That is the one thing I did see with a battery connected, the led did flash faster. I am sure the board is fine, the mesa boards seem very robust. It is unfortunately the just me the user who does not know how to use it in this instance.

@Darran,

Can you come closer to your exact problem. Is it the way you connect item's in hal other item's?

I don't use Mesa, so i can't help you with pre configuration's. Only for parport and ethercat i can help you in plasma world.

Hi Grotius

My problem is connecting in hal. The mechanics of the machine i am good with as I built it, wiring again is no problem. The main issue is I do not yet know anything about Linuxcnc, I was a computer admin so am computer literate I just dont know the software yet. I bought the cards and decided on Linuxcnc when I did not have such a rush to get the machine working, I now have work for it so need it running.
The thcad is all connected and I can work out the offsets required I just do not understand what needs to go in hal to make it work

Here is a simple example from my system, used daily.

John

Here is a screen shot of my pinouts for the 7i76e for the wiring of the THCAD. Yours should be similar Note that my system is non standard as I blew something up and PCW wrote me new firmware that mapped the Encoder B to Encoder A so ignore the numbers in brackets



Set the THCAD link to be 1/32
So once again halshow will be your friend. With the 9 volt battery connected, you should first check the encoder pins and one of them should be close to 90% of the 1/32 frequency based on your calibration data. Then it is a matter of scaling the reading back to a voltage reading. You can do this using standard hall components, but I wrote a component to do it, If you look through this section, you will find it.

Hi John.

I saw this config earlier in the thread and wanted to try it. Is there any other setup required to use it? Hiw do you input the required voltage?

Hi Rod

I have all the physical connections complete. Its the code in hal that is causing me issues

Just hook a known voltage (9v battery) to the input of the THCAD card for a quick test. You will need a voltage divider between your THCAD and plasma machine. It can be a built in one or home brew. The THCAD is pretty input over voltage immune. Assuming you have a US single phase plasma you should be good with anything greater than about 15:1. Read the THCAD manual as it has instructions for selecting a single series resistor for simplicity. If you have a HV/HF start machine then your divider will need to be a little more complex to keep the rf out of the THCAD.

John