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Hello all it's been a number of years (3+) and i've finally got around to getting this working on this. I graduated as a mechanical engineer and felt comfortable enough to understand this stuff now.  I was able to connect my mesa 7i96, problem was that my linux distribution had issues connecting to the 7i96. I basically upgraded to the latest linuxcnc (currently on debian 12 with linux 2.9.3) and i have the machine moving using AXIS, for some reason when i try to setup the QTPlasmaC and it will not operate .

Here are the errors i'm getting(see image attached), what doesnt make sense to me is that my jitter is the same as when im using AXIS... and AXIS works great!

Honestly my only goal is for the machine to cut metal with the plasma torch and have a functional torch height controller, i dont care which GUI is used.

If anyone could please help me get this machine going i'd greatly appreciate it!!! I have projects that require plasma cut parts and i'm desperate for this machine to work.

Thank you in advanced , have a great day everyone!


 

Reliable computer will not help you, any computer will do.
The thing with plasma is they create huge amounts of interference when striking and arc, so grounding and proper shielding are mandatory.
Normally you can get away with Mesa 7i96S and THCAD, and they are extremely reliable.
Here are some ideas:
forum.linuxcnc.org/show-your-stuff/38547...plasma-build?start=0

Good afternoon everyone

Can you please help me with how to configure the Z axis drive and recognize the THCAD2 as an encoder? I have tried several times without success.

 

When trying to move the axis, an error appears calculating the movement of the Z axis.

 

This is the INI file type configuration

 

this is the HAL type file configuration

Please, can someone guide me?

INI and HAl files attached


 

 

 

There should be three of encoder A, numbered 0, 1, and 2. Click the arrow next to the encoder you want for arc voltage.

If you are using an encoder for ohmic comp you need to do that manually after PnCconf has completed, the default ohmic sensing for QtPlasmaC is done using a solid state relay rather than a THCAD.

You have 1 encoder on Mesa 7i96S and 6 more on Mesa 7i77, so you can use any of those for THCAD.
The issue of it not working might be changed encoder number in hal in the firmware, so use the "show hal configuration" from the "machine" menu to check what number is assigned to Mesa 7i96S encoder, should be 0 or 6.

Hello, I have 2 7i96s boards. The first one has the original factory firmware and is used for lab testing. I tested it with THCAD2 on the encoder input and was successful in receiving the frequency and reading it, showing the frequency speed. However, to my surprise, on the client's machine where there is another 7i96s that was updated to work and recognize the 7i77 plus the 7i84, I did not get the same result, it cannot read the frequency. After much analysis, the only thing different in the HAL programming is the configuration sserial_port_0=3000, which is different to enable recognition of the 7i84. Setting encoder-mode to 1 did not help. Why am I not getting the same result? Is there some configuration that I am forgetting to do?

 

Hello everyone, I'm already on the client's machine, I'm trying to apply part of what worked in the lab test with 7i96s and
I'm trying to do the same client configuration on the 7i77 that was done in the lab on the 7i96s. But on the 7i96s I have to put:

setp hm2_7i96s.0.encoder.00.counter-mode 1

setp hm2_7i96s.0.encoder.00.filter 0

setp hm2_7i96s.0.encoder.00.scale -1

and will read the frequency applied to ENCA+ and ENCA- of THCAD2.

However, the 7i77 does not accept this configuration. What is the procedure to make the 7i77 change the encoder to mode 1?

 

Does not show hm2_7i96s.0.encoder.00.velocity

 

How to configure the 7i77 encoder to accept frequency?

 

Thank you, I will follow your guidance and post step by step here.

3rd The big problem is that LinuxCNC does not understand that only a frequency signal from 100 to 1000Kz determines the feedback of the Z axis position.

I think this was already discussed  in another thread. I think the best way to do this is
step by step

The first step is to scale the encoder velocity into the desired units (mm?)
This can be done with the encoder scale parameter, but it's likely you will need
an offset, in which case you can feed the encoder velocity through the offset
component. When this is all done you should have a direct scaled position signal.

To calculate the scaling you will need to move the Z axis to 0 position, read the
encoder velocity, then move Z a known distance (preferably near full range of motion)
and then read the encoder velocity again,


The second step is to feed this signal into the feedback input of a PID component.
this PID component will force the Z axis to follow the Z axis position command from
LinuxCNC.

If you setup a normal analog + encoder feedback LinuxCNC configuration
with pncconf for 7I77 hardware, all of setup/connections/components will have been created
for you and the main change that needs to be done is substitution of the scaled/offset
encoder velocity for the encoder position that pncconf setup.

 

I just need the examples to move forward
A while ago I was having another difficulty, with the automatic tool change, the LinuxCNC help files are in English and very confusing, only with a video showing step by step I was able to get what I wanted, below is the example video:

Below is the result of this example applied to my machine

www.youtube.com/shorts/OWihZHUuwew
I'm not as lay as you think, but I need a little push from some example code in a video to show the control of the plasma torch?

Good afternoon

I will try to be as precise as possible about what I am looking for, although the language barrier does not help.

1st The 7i96s electronic board was designed with an encoder input ENCA+ ENCA-, ENCB+ and ENCB+. This would be the basics to connect an encoder with output A and B and for everything to work perfectly.

2nd I need to connect only and exclusively to ENCA+ and ENCA- a single frequency signal from the THCAD2 board that resets to 100kHz in the low position and resets to 1Mhz in the high position. This has already been done successfully.

3rd The big problem is that LinuxCNC does not understand that only a frequency signal from 100 to 1000Kz determines the feedback of the Z axis position.

I can't believe you don't understand this, given your extraordinary skill. Some people want to tell me that I ask questions that are too obvious to be answered by the masters. So I challenge the creators of this technology to prove that they can do this simple application by showing me examples.

Unfortunately, I really believed in the technology from the manufacturer MESA, and I received a lot of help from Mr. Peter and this forum. But it seems that now I have reached a limit where no one can help me with this. To make matters worse, I have not yet found anyone willing to provide the service, even if I pay. This is sad, because MESA has everything it needs to be widely used to replace major brands. All that is missing is more examples and support from professionals like me.

Since you asked what I want to achieve, it is simply to control a hydraulic cylinder that repeatedly hits a metal plate, but this hit has to be at the right height down to the millimeter. The actuation output is controlled by the 7i77 electronic board and it plays from 0 to 10 V positive to go up and from 0 to -10 V negative to go down. Next to this cylinder there is a linear inductive sensor that has a 0 to 10 V positive output that at 8 V is with the cylinder high and 0 the cylinder low, this height return with millimeter precision goes to the THCA2 board that sends this information to the 7i96s board, MY GOAL IS that in the G code I can control z000001.000 or z000001.50000 to drill deeper or less deeply. Did I understand the objective? Is there any better idea, or is it very easy and obvious?

After reading this several time i still can not figure out what you are asking! I am sure you are not asking for wiring as you can do that easily, so...
Would be much easier if you would tell us what you are trying to do/achieve/get to.
In short, the encoder velocity from the THCAD is feed to PlasmaC component (not GUI) where it is used to control the Z axis position during cutting, this all goes through a PID loop to keep the set voltage value inside the tolerances (usually +-1V) and the output of that PID loop is sent to external offsets component to do the actual motion of the Z axis.
There is much, much more to it, and for that you would have to go through the PlasmaC component on github, several thousands of lines of code there to explain what you are asking.

Good morning, friends

Does anyone have an example of how the Z axis is connected and controlled in the axis movement for controlling the height of a plasma torch using the THCAD2 board on the ENCA+ input of the 7i96s? I am developing it for other purposes, but I think the example can help. It needs to be in LinuxCNC 2.8.4, if anyone has an example, even a simple one, it will help.

 

 

Good morning Master PCW

I made the suggested change and it was not successful, an error appears, can you please help me?

The image below is before changing the line 214

 

The image below is after changing line 214

 

The image below is the error reported after the change

 

Attached are the error and hal configuration files


 

 

Please, can you help me?
 

One obvious change is that the Z axis feedback must come from the encoder velocity
(= scaled THCAD2 frequency)

net z-pos-fb hm2_7i96s.0.encoder.velocty