Remora - ethernet NVEM / EC300 / EC500 cnc board

In our tests, the tracking errors began with frequencies of 2.5kHz in signals A and B of the encoder. If we do a quick calculation for 100ppr and 3000rpm, we would have 3000/60=50rps and 50rps*100ppr=5khz, therefore these are double the 2.5kHz that I mentioned before, here the problem is that you increase the rpm a lot, something else to mention here is that at 2.5kHz I already obtained a very deformed signal at the output of the optocoupler, you can see the links that I left in the previous comments, greetings

I don't really understand it's becoming too technical and the lack of knowledge plus Google translation doesn't help matters I want to use this card for an amateur plasma CNC

Hello Beauxnez, firstly could I ask you what your native language is? I speak Spanish and some English, it might help you to know this in case you want to communicate with me in another way.
The problem becomes technical because it is a hardware design problem that these boards present, these boards were not designed to attach any encoder to the input pins and even less so for an encoder that varies signals A and B quickly.
The THCAD modules, for example, would have to be connected to these boards through an instance of the QDC module or encoder module software (the latter I don't know how fast it can count) I advise you to take a look at the LinuxCNC documentation more specifically 1 -Plasma Cutting Primer for LinuxCNC Users and 2-PlasmaC User Guide, then in this forum there is a lot of information about THCAD and MESA boards.
The development of the QDC module has been a challenge at least for me as I had to code it, thanks to Scott for his ideas on how to do it, after all that work I carried out functional tests and found many tracking errors for closed loop configurations due to because the integrated circuits that protect the inputs (optocouplers) do not switch fast enough and the signal that reaches the microprocessor is quite distorted.
Having said all the above, I could tell you two things:

1- Can the NVEM/EC300/EC500 boards be used to connect THCAD encoders, etc.?
Yes you can do it.
2- Can this connection be made directly to the inputs of these boards?
Yes, but it would be very slow, this to follow an axis (max velocity700mm/min encoder 1000ppr or 4000 counts), I imagine that THCAD also has problems.

Another thing I can tell you is that this is a project that is being developed so don't expect to connect everything and have it work the first time, greetings

I was born in Portugal and I live in France not far from Bordeaux.
Ok I'm going to order this card to try at worst I could always use it with Mâch3 I suppose?

How much do those NVEM stuff cost?
If they are over 100$, get a Mesa 7i96S.
I used several Mesa 7i92 for plasma machines, they are in use daily, so less that 100$ normal price ( i have to pay at least 200$ for one of 7i92) but not for beginners for sure as it is sensitive to miss wiring and EMI, so great care must be taken in regards to shielding and grounding.

a NVEM costs 70 euros