AX58100

Yes, it went well. Both your card, COFHAL, and SOLD's system were able to start and are now working.

Background: I have been making a few EtherCAT client cards, just to see how it can be done, to learn about EtherCAT and eventually use a card in my plasma cutter which is slowly being built. If all goes well.

I publish the project on github.com/MetalMusings/MyOwnEtherCATDevice and I made a series of Youtube video as I learned things along the way.

The card we were working on was the EaserCAT 3000
image missing https://github.com/MetalMusings/MyOwnEtherCATDevice/raw/main/Utils/Pictures/EaserCAT-3000.png

Looks great!
Shame it seems that it does not have an analog input, with one of those you could of done the arc voltage reading directly without the need for a mesa pcb in between.

Well actually you seem to have a microcontroller on there as well that most likely has an ADC, why not use one of those? I did not check the schematic but will take a peek at somepoint.

Entirely possible.
There is an STM32F407VGT6 but you can switch it for your favorite MCU if needed.
Now, I am not an electronics engineer even if I do this kind of things. With that said I imagine one would need some electric isolation before the arc voltage reaches the MCU pins. One "just" needs a circuit to read the arch voltage that the MCU can read.

These are just my opinions but, you dont need isolation and you would not design to read the raw arc voltage. Most decent plasma's will give you a divided arc voltage output, most common divider ration being 50. So an arc voltage of 100, would read as 100V/50=2V. You probably only need some filtering, input buffer and over voltage protection.

I took a quick look at the AX schematic, seems its only used as a gateway and none of the "special" features are used. This begs the question, why the AX instead of the LAN9252? To me the AX seems hard to get, are there benefits to use the AX as a gateway?

What are your plans for the plasma build? Do you need the MCU to do the step/dir? Or could you just get an ethercat drive and let that handle the motion side? Then you could probably use a much simpler (cheaper and smaller) MCU for IO, Analog input, maybe an encoder for pendant etc.

Unfortunately my Herocut plasma gives full arc voltage. I also have a THCAD 300 card to interface with.
It's a possibility what you say. Anyone wishing to give it a go have all the schematics and pcb layouts
as a starter, and all software needed to deliver values over EtherCAT on github.

You know the path isn't always that straight when I develop things. I started with the LAN9252 and it is more or less coincidental that I went with the Ax58100. And you are right, they are used as gateways. In the setup with a MCU I don't really see a difference, can go with any of the two. They are both available on aliexpress and cost about the same. I have gone back to the LAN9252.

For the plasma build, my initial thoughts with EaserCAT-3000 card and the Ax58100 was to use existing stepper motor drivers and have the card do pulse/dir. While that now works, I have skipped that path and are now going to use ECT60 Ethercat stepper motor drives. My own cards will be used for Digital IO (limit switches, float switch, break-away switch, torch on), and for reading the THCAD-300.

Here is the reader for THCAD. A stripped version of the EaserCAT-3000, with LAN9252. The MCU reads PWM frequency on one pin. Could definitely use a smaller MCU, but it is also easy to reuse what I know works.
image missing https://github.com/MetalMusings/MyOwnEtherCATDevice/raw/main/Utils/Pictures/EaserCAT-4000.png

Digital IO. This card does use the DIO of the LAN9252 directly, no MCU.
image missing https://github.com/MetalMusings/MyOwnEtherCATDevice/raw/main/Utils/Pictures/EaserCAT-5000.png

I find that the documentation for the Ax58100 is lacking for the special functions, like stepper motor driver. There is a reference application supplied that uses TwinCAT to drive a stepper motor. I guess one could try to understand how all that works, but I haven't. And that is all info I know of.
 

Thanks for the detailed answer. Its always a bit difficult to comment on projects you dont know about.

The asix chips look nice on paper but then again if you pair it with a MCU, how much benefits are there, I don't know? I was just wondering if there are benefits from the programming side so that it would make sense to use that instead of the LAN9252. I have 0 experience with the asix chips so I would love to hear from people that have used both.

Although both maybe available on aliexpress, I would say the LAN9252 is far more obtainable than the asix chips. I typically try to scan something like octoparts for any "special" components I might use, at least if there is even a small chance I make something more than one. A quick look and just digikey and mouser stock these in the thousands. I lost my mind on the chip shortage so now days I try to find multiple sources for parts and if I'm lucky multiple alternatives.

Good luck with your plasma build!