Do we need a Plasma Touch Off HAL component ?

08 May 2017 02:22 - 08 May 2017 02:22 #92800 by ksgeek
I have not done a complete compare yet, but the from the thread you liked to seem to be what I started with. I pulled it down from the Proma website. I have everything wired up I think, but when I do rapid movements over 300 inch/min I get following errors. If I increase the FERROR values. then we start losing steps. I have reviewed the timings of our drivers with the linuxcnc docs as I can find them, and we have things correct.

When running a straight stepconfig project we can do rapids up 500in/min with out any errors or lost steps as far as I can tell from our testing so far.

That is why I moved to the gmoccapy+thcud component to resolve the following errors and improve the movement speed.

This was all with 2.7 stock install. I have went back and tried the thc_toma config with the dgarr/external_offsets branch yet. We are currently transitioning our control panel from prototype hair ball to a permanent layout, so I can't test anything at the moment. :(

I do not want to hijack this thread too much. I can post these concerns on the other thread.

Last edit: 08 May 2017 02:22 by ksgeek.
08 May 2017 02:44 #92801 by rodw
Tom, don't worry too much about the hijack.

The external offsets won't help you as you have an external THC. External offsets will only help if Linuxcnc is controlling the z axis totally. it offers a PID based control that uses the torch voltage (usually read by a Mesa THCAD daughter card) as a feedback signal.

Its so new I don't think anyone has actually tried it on a real machine yet

Tommylight is the expert with the config I linked to as well as Proma and steppers in general. I'm sure he'll chime in
26 Dec 2017 05:55 #103614 by grijalvap
I have been working on a component for THC control, it is similar to external offset controller, however, the component does not include PID.
Attached are the code and the state machine diagram.

File Attachment:

File Name: thcsm.comp
File Size:16 KB

I'm not a very good programmer but the component is working I like to know your feedback about.
26 Dec 2017 06:14 #103616 by rodw
Looks great on first glance. Well done!I will go through it when I have some time in the next few days.

The only thing I saw programming wise is that is not normally good practice to run a for() loop in an interrupt service routine but I did not look at what was doing. But hey if its working thats a great achievement!

Could you post some example G code for it?
27 Dec 2017 02:09 #103724 by grijalvap
I have tested this component manually in the past and it works ok, however, today I tried it with a g code as RODW suggested.
and I found a problem the g-code executes correctly until M03, the start command is properly sent to the thcsm component and the component start the sequence and it works properly and return the move on command for the g-code to continue but it never continues, I tested the set up with other configuration and it works well.

there is any restriction to use a step generator as stand-alone.
any clue?
27 Dec 2017 04:07 #103728 by rodw
Its a bit of a long shot but to you set spindle at speed?

In my plasma setup, I do it like this so its on all the time.
# ---setup spindle control signals---
net spindle-at-speed           =>  motion.spindle-at-speed
sets spindle-at-speed true

In a component such as this one, I envisaged this pin would be set true when the touch off routine is completed and it is good to move off.
27 Dec 2017 04:58 #103729 by grijalvap
You get the target.
I set the motion.spindle-at-speed pin to true and it is working, thanks a lot for your help
Tomorrow I will post the G-Code and configuration files.
Thanks again.
27 Dec 2017 05:28 #103731 by rodw
Great. The other Gotcha I found was that you need to tie M3/M5 into the arc enable otherwise if you have an estop or crash the torch, the torch will still be firing. (Which is a bit of a worry when it falls off its magnetic breakaway and the plasma power switch is in the other side of the table!

I think the right pin is motion.enable

I am hoping to have some time to play with your config this week.
27 Dec 2017 23:22 - 28 Dec 2017 04:20 #103768 by grijalvap

File Attachment:

File Name: Test_2017-12-27.hal
File Size:10 KB

File Attachment:

File Name: Test_2017-12-27.ini
File Size:4 KB

File Attachment:

File Name: custom_pos...2-27.hal
File Size:1 KB

File Attachment:

File Name: Test_2017-12-27.ngc
File Size:1 KB

File Attachment:

File Name: thcsm_2017...7-3.comp
File Size:18 KB

As i mentioned here you have the files
I have included 3 inputs for crash sensors, these sensors can also be used as floating switch.

I will double check the code regarding estop.
Last edit: 28 Dec 2017 04:20 by grijalvap.
01 Feb 2018 05:52 #105267 by grijalvap
did you have some chance to test the comp?
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