Runaway torch THCAD-10 + PlasmaC + Hypertherm 45XP

radek_marko wrote: Snowgoer - are you delicately suggesting that LPT might not be capable of performing well on counting impulses from THCAD-10?

He's not delicate. He's pragmatic. Sure some people have done plasma with a parallel port but given the cost of your 45XP, why would you use non-industrial hardware to save $100? That is a very small percentage of the overall cost of your plasma build project.

Yea, Rod basically hit the nail on the head with what I was getting at.

Hypertherm is arguably the best plasma power source you can buy. The THCAD is extremely capable. So you have basically purchased a Ferrari with the bells and whistles, but then opted to drop in a motor from a 1986 Chevy S10 pickup truck.

I honestly think that while you may get things to work (by limiting the performance), you're causing yourself a lot of unnecessary headaches. Probably just scratching the surface with the THCAD issues.

Did you use a RTAI or the RT_PREEMPT iso? Switching to the 7i96 will require you to switch to a RT_PREEMPT kernel if you are on RTAI. If you're already on RT_PREEMPT, that would be a source of issues for Parallel anyways.

I think your setup uses 2 parallel ports, so I'm not sure if you have a lot of I/O's or what, but if you do, the 7i76e is even more capable yet. That said, most guys can get away with the 7i96 on a plasma table and still have empty I/O's.

How fast is your base thread?

The base thread frequency will determine the maximum count rate of the software encoder

At a 1/128 division ratio, the maximum THCAD output frequency will be about 7 KHz
For the software encoder to count this reliably you need an absolute minimum of 14 KHz
(~70 usec) base thread but this assumes 0 jitter. Allowing for jitter, a safer base thread rate
would be about 25 KHz (40 usec)

I've tried F/128 settings and it's giving some hope


PCW - here are settings from INI file and HAL Latency test
BASE_PERIOD = 64000
SERVO_PERIOD = 1000000

That seems usable.
Do you get latency warnings while using LinuxCNC?

Tommylight - no latency warnings now, I used to have latency warnings, but isolcpus fixed the issue.

I still haven't solved the PREVIEW issue reported on the other post .

Again - thank you for all of you for the massive support!

radek_marko wrote:
I still haven't solved the PREVIEW issue reported on the other post .

That is due to other languages if i remember correctly, but i think it was already fixed for German and it is not present in English, but again not sure about it.

I was struggling to make THC fully operational via LPT. As I'm starting to do more cuts I'm following your advice and I've just ordered MESA 7i96 card. Now I need to rewire the control box and reinstall OS...

So, I have an update on the integration of THCAD-10 and MESA 7i96:



After sorting out few problems I've managed to get the expected voltage in PlasmaC.