Remora - ethernet NVEM cnc board

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16 Dec 2023 20:13 - 16 Dec 2023 20:16 #288364 by beauxnez
I launch stepconf I name my machine remora-nvem then I replace my .ini and .hall file with the one remora?
Last edit: 16 Dec 2023 20:16 by beauxnez. Reason: I launch stepconf I name my machine remora-nvem then I replace my .ini and .hall file with the one remora?

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16 Dec 2023 20:37 - 16 Dec 2023 20:38 #288366 by beauxnez
rbobey1989
you mean it's better for me to go with an NVEM card?
Last edit: 16 Dec 2023 20:38 by beauxnez.

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17 Dec 2023 08:33 - 17 Dec 2023 08:51 #288381 by rbobey1989
Hello Beauxnez, I have never experimented with an NVEM board, I don't know what optocouplers that board uses, but I imagine the same thing happens with the NVEM board as the EC300 and EC500 boards, what I wanted to say before is that to use the QDC module the first thing would be to obtain A B and Index clean signals and for that it is necessary to introduce some separate hardware, in my previous tests I have documented the problem and since I have solved it with an ADUM1200 digital isolator, of course this solution is only for testing, we would have to make all this more robust, that is a separate connection board for the encoders, I leave you the post where I referred to the topic, problem and solution,  greetings
Last edit: 17 Dec 2023 08:51 by rbobey1989.

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17 Dec 2023 09:12 #288383 by Murphy
@rbobey1989, how fast can the ec500 optocouplers handle do you reckon? Say a 100pr quadratic encoder. Spindle at 3000rpm

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17 Dec 2023 09:42 #288384 by rbobey1989
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
The following user(s) said Thank You: Murphy

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17 Dec 2023 13:00 #288396 by beauxnez
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

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17 Dec 2023 13:57 #288405 by rbobey1989
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

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17 Dec 2023 14:15 #288408 by beauxnez
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?

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17 Dec 2023 15:29 #288413 by tommylight
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.

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17 Dec 2023 15:42 - 17 Dec 2023 15:44 #288419 by beauxnez
a NVEM costs 70 euros
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Last edit: 17 Dec 2023 15:44 by beauxnez.

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