emonTx V4 as a power quality monitor

Hello everyone,

I am new to this community and would be very grateful for some general experience / feedback.

I am looking to conduct a domestic power quality and load analysis, and after looking at some of the open source hardware projects, OPQ etc, the openenergymonitor arrangement looks to be a great source of both well tested hardware and software.

I would be interested in understanding the available sampling rate using the 3 phase emonTx V4 and emonVs, I am looking to sample 2 voltage channels and 6 current channels to ideally 40 samples per cycle. Is the emonTx capable of this level of resolution?

Thank you in advance


Welcome, Mike, to the OEM forum.

You can do no worse than download emonLibDB and look at the code. The sampling rate is constrained by the necessary calculations required for the rms and power values, and particularly those to compensate for the transformer phase shifts, and even more seriously when a 3-phase delta-connected load is concerned. So the answer depends very much on what you want to do with the numbers once you have them.

Thank you for your advice Robert. I am working my way through the code just now. It looks like the emonTx and emonVs will do the trick, especially as I won’t need to utilise all of the calculations.

And the best of luck with that. Your question was so open that it was not really possible to write much more than I did. If you come across any specific points that need explanation, ask.

If you appear to be hitting a brick wall with regard to performance, you might want to seek out everything written here about the STM32. This would have been the preferred choice for the emonTx4, but it was availability that dictated the AVR-DB.

Thanks Robert, will certainly come back with qs as they arise.