This looks like an address problem perhaps, or possibly some other communication setting issue. Did you try to set it up as I have above? At least for testing purposes.
If you did do so then it may be another issue, possibly with a hardware definition; if you can run the following commands while connected to the Neuron and paste the output here we may find the problem.
Found out that EMC was not an issue, but the LED power supply. I added a 10k resistor in parallel to the 0-10V input which fixed the 0V problem.
Only poor thing now is the bad behaviour of Mervis with the AO extension board. I added a ramp for smooth dimm up and down, but it's actually not smooth but rather stepwise:
Any idea how to fix? Maybe the problem comes from the transformation "to_uint(real)" ?
Unfortunately the timing is too quick to be done by anything but a direct line to the CPU (Raspberry Pi/Arduino GPIOs are such a line to the CPU, which is why it works at all). As such it's not possible to use with Neuron or UniPi 1.1 out of the box. With some warranty-voiding modifications it may be possible to connect the device to an unused RPi GPIO, but I cannot recommend this action unless you are fully comfortable taking the risk and voiding the warranty. I also cannot provide instructions on doing so.
This link describes API, how to Mervis RT access the Mervis DB but you can create the same API server implementing just the saveData function (eg. in PHP), point Mervis RT to this server and do whatever you wish to do with the data.
I believe so, yes. Normally PWM and analog outputs are separate functions handled by different outputs, but UniPi 1.1 does not have PWM support unfortunately. The fact that the analog output is PWM-based is coincidence, though as I described above it could be turned into a non-analog PWM output with a few hardware modifications (though these would void warranty).
On Neuron you would use an analog output toggled by a digital (transistor) output to create the PWM signal, but as UniPi 1.1 only has relay-based (rather than transistor-based) digital outputs this is not going to be possible, as they cannot toggle with anywhere near the required speed, and have a maximum number of state changes due to their physical nature anyway.
The main advantage of relay outputs is they can handle orders of magnitude higher voltage and current, which is why the larger Neuron models have both (S103 only has transistor outputs).
It might be best to try again with the latest version. The EVOK version cannot be easily found since it's done via GitHub versioning, the easiest via is by checking which installation file/image has been used.
Apologies I did not get back to you earlier, but do try it with the latest version.