Add support for the OPC-N3

[dhhagan]

I have just received an OPC-N3 and can thus begin this process!

[Mi-Ch]

Have started work on support for OPC-N3 in py-opc?
//Thank you for your great project!

[dhhagan]

Hi @Mi-Ch I have not yet, but I can if there is a demand for it...I'll try and get started within the next week or so.

[Mi-Ch]

Thank you @dhhagan ! That would be great. We just received two OPC-N3 and we are setting up small comparison study with PMS7003 (x2) and SEN0177 (x2).

[biogis]

Hello,
We'll also need OPC-N3 support soon. We worked with the N2 but decide to go further with the last sensor.
Great project also, thanks for the job you are doing.

[dhhagan]

Oye - I'll do my best...have a bunch of papers to write and a dissertation to finish up, so hold on...ha

[Mi-Ch]

@dhhagan I know the pain, I'm in the same situation ;(. Dissertations, papers....but preparing new measurements/experiments is much more interesting than writing about old ones.

[dhhagan]

Alright @Mi-Ch and @biogis - I will get to this this week (hopefully sometime tomorrow). In the meantime, it would be great if you (and anyone else reading this) took a second to add to the mentions page to let me/others know how you're using this software. If nothing else, maybe it will convince some other PI's that releasing OSS isn't a huge waste of time!

[dhhagan]

Alright - an update: I just set aside some time to implement this into the package, but the Alphasense-provided documentation on the SPI protocol is totally incomprehensible. I would suggest anyone that needs this to operate the Alphasense OPC-N3 reach out to Alphasense directly and ask them to either add it themselves, clarify their documentation, or hire someone to do it. I apologize that I wasn't able to get this working for you all, but I just don't have the bandwidth right now to deal with them.

[biogis]

It might be a dummy question, but the failing connection is due to the spi or to another firmware in the opc which is not recognised py the opc.OPCN2 function?

My first error is by opening the connection using the opc.OPCN2() function, and it mentions a firmware error.

[dhhagan]

@biogis Yea, I would say that's expected. When you initiate an instance of OPCN2, it automatically issues the read_info_string() method to get the firmware version so that it knows which other methods are unavailable. For the OPCN2's, the firmware versions were in the range 15-18.2; however, on the OPCN3's, they switched it up, and now the firmware versions are stuck in v1 (i.e. v1.17) - not sure why they did that...

Anyways, as far as I can tell, they changed all of the SPI commands and added an extra command byte which means that none of the old code will work - some of it is similar, but the one I don't understand is how to turn the device on and off, which is kind of important...

[biogis]

Ok, I understand better what the issue is. I'll ask alphasense what they have been doing. Thanks for your prompt answer. I'll send the answer of alphasense on that issue.

Best luck for your diss...
Manu

[Velivole]

Hi everybody,
I just wanted tu port my project from the N2 to the N3 an stumbled upon some errors and then this thread. This doesn't sound very good, what Alphasense did there.

I am not that kind of pro to work on this github project actively. But is there anything I can do (i.e. contact Alphasense) to help make things work? We are really dependened on a working N3.

Thank you very much!