Powermax45xp with serial interface, how to connect this inverter with linuxcnc

31 Dec 2017 16:39 #103901 by Grotius
Hi Nerd here again,

I have now a Hypertherm Powermax 45xp with cpc and serial interface in my shop for testing on Linuxcnc.

The most important issue to use this type of powermax is the metal marking option. This works very good. And my customers
use this option because of the CE qualification of their steel product's. All their pieces must be coded to get the CE qualification on
their output product.

So what i want to realise are 2 important things.

1. Connect the stand alone linuxcnc application to a proma thc and use the 3 input signal's from the proma thc to
move the z-axis up and down. So this configuration i want to realise first.

2. Connect the stand alone linuxcnc application to the hypertherm powermax serial interface. Then i can read and set all the available hypertherm value's. This connection make's plasma cutting to a next level.

Here i have attached the serial protocol. I have also the serial connection cable ordered with the powermax.

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The first thing's i need to know is the best en simple way to manipulate the z-axis while cutting.
I read in serveral document's off Rodw it can be done with "External offset's" or with direct hal manipulation.
I found out that there a very complicated hal code's to use the proma thc.

Has someone a good advise to start with?

The stand alone application is now running without errors. So i can start with the next thing : Z-axis manipulation.

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31 Dec 2017 23:47 #103914 by rodw
Michel, I don't know anything about the proma THC but they have a working Linuxcnc config on their web site. See
Tommylight on this forum uses Proma a lot so he may be of help.

With regards serial communication, one option is to use a Mesa 7i76e with revised firmware that exposes the RS-422 UART used by Mesa's smart serial interface. See this thread

Because Hypertherm uses a RS-485 4 wire interface, this should allow communication via the modbus protocol used by Hypertherm.
However, you will need to write a hal software component in C to access the 7i76e UART as there is no such driver in the Linuxcnc distribution.

I've not done anything with my plasma machine for some time due to lack of time.

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02 Jan 2018 19:44 #103961 by Grotius
Hi Rodw,

Nice to hear you. I hope you have a lucky year !!

This summer i was starting with Linux tutorials. Understanding Linux (python) programming is for me a very difficult thing to learn.
A few weeks ago i started again with learning jt tutorials. It takes many, many time to make things working and understand how it is working. Respect for the linux programmers.

At this moment i have the basic cnc item's working in a stand alone application. I have tried to simplyfie the python programming to
a python basic level. The screen layout is not finished at this moment, it is only for functional useage at this moment. Later in my project i finish the screen layout. This is when the THC funtions are done.

For now it's important to make the THC software working, starting with the Proma THC on a standard break out board.
When this is working i can alway's look at the mesa card's and other possibilities in the future.

Also i want to communicate with the Hypertherm with the Modbuss system. So i want to look if this can be done with the
standard com1 port on the pc.

The Toma thc program looks very difficult in the Hal section. So i am considering to modify this pyvcp layout into a stand alone application with the layout made in Glade. This hopely takes a few evenings to do. Then it's working good, but in my opinion to complex build.

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02 Jan 2018 20:15 #103963 by rodw
Yes, 2018 is going to be an amazing year!
Google has a very good tutorial on Python programming
As a casual programmer I struggle with using it sometimes too but it is a very powerful language. You can do in a few lines what can take 100s of lines (1000's?) in other languages and there is a Python library for almost anything.

Nothing about plasma is easy in LinuxCNC. I think we all try and jump in too fast. With your background, I think I would try to get the Proma config going exactly how the author intended and use the same pins etc. The screens can come later as its easy to change from one GUI to another once you have a working system.

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04 Jan 2018 12:03 #104015 by tommylight
Just to be clear, i did not make that config from scratch, most of it was taken from THC300 config and modified, and for all intents and purposes it is a magnificent piece of hal code, so whoever wrote that, thank you.
As for serial interface i can not help with it,
For Proma THC if it is the 150 variant or the new one with UP/DOWN/ARCOK , they work perfectly with that config, i have 5 machines working with them all day every day.
Side note: due to lack of time i could not work on a project that would include some AD converters set to monitor the plasma voltage ( using THCAD, have one wired and ready) and sending the analogue values to plasma cutter for current adjustment ( can be done using the spindle output on the 7i76 or 7i76E or 7i77 ), also making a pyvcp pannel with preset values on screen for easy access.
I need 70 hour days!!!

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04 Jan 2018 19:26 - 04 Jan 2018 19:27 #104030 by Grotius

Yes the Proma works very good. There is al link of my company at their website. Mostly i order them by 10 pcs.
So maybe if you want to order in the future you can get a special linux price...
On wich branche of inverter do you want to use the power setting by pwm i think?

I will update this thread for the serial communication link.

When do i become a platinum boarder? hihi
Last edit: 04 Jan 2018 19:27 by Grotius.

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17 Feb 2018 18:43 #106083 by grijalvap
I have written, very basic python component to communicate with hyperterm 85 it is working.
as I say it is very basic but works well to set and get the pressure, current and mode
also Gets the errors.

I have tried it with a USB to rs485 converter.


File Attachment:

File Name: hpmx.py
File Size:4 KB
The following user(s) said Thank You: Grotius

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17 Feb 2018 21:23 - 17 Feb 2018 21:25 #106097 by Grotius


The code is smaller then i thought, perfect !!!!

Many thanks, i will test this when order is delivered.
Wow i didn't expect this today !!

I am currently building a plasma inverter for my own company to sell with the machines.
It's like a Hypertherm Powermax, but then a little better and watercooled inverter. You can easely improve a Hypertherm concept by
placing the air valve at the torch head. Also the ingnition time out can be a little longer in time.
It needs a modbuss reciever with a few i/o. When this story with a hypertherm works, it wil work also with other modbuss
devices i think.
Last edit: 17 Feb 2018 21:25 by Grotius.

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17 Feb 2018 21:28 #106098 by grijalvap
Nice, you will need to install pymodbus in order to the component work
The following user(s) said Thank You: Grotius, thefabricator03

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17 Feb 2018 21:40 #106100 by rodw
Very nice. It always amazes me how much python can get done in a few lines of code. It can do what would take 1000 of lines in other languages in less than 100. There is always a module to do what you want. I always thought this would be pretty easy in python.

How to install it is covered here

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