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Home Energy Monitor
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A low cost, high performance energy meter for my home.

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  • Home Energy Monitor 3 months ago

    Thank you! I would like to take credit, but configuring the graphs only took about 10 minutes of my time using Grafana - which is a really great tool.

  • Home Energy Monitor 3 months ago

    Hi David

    I'll try and answer your questions, and go through the changes you will have to make for this to work. It will take some knowledge of python and modbus.

    1. The modbus address is the second argument to the "Instrument" class constructor I use on line 9. It is 1 for me, and for you can be any number that you set your address to for that particular meter.
    2. You can create as many instances of "Instrument" as you like. The minimalmodbus library handles them all using the same port (if that is what you are doing).
    3. I used threading to create a new modbus request every second. You should not create a separate thread for each Instrument (unless you have some kind of mutex), because you will want to to evenly space your modbus reads. You could either use a single thread that iterates over your instruments, or use another technique to schedule your modbus requests.
    4. You will need to log to a different measurement on the DB for each instrument, or use some other method (different databases, different keys) to identify which instrument the data is from.
    5. The modbus address table and scaling for the different type of meter is likely to be different, so you will need to figure this out. Lines 17-20 map the relevant addresses to python variables, but only for the meter that I am using.
    6. InfluxDB can run on a variety of architectures- I assume you mean a x86 or amd64 architecture by "an Intel". It can run on both of these with Linux, but I'm not sure that it works for x86 with Windows.

    Good luck, and please ensure that you get someone with the suitable qualifications and experience to install your meters.

  • Home Energy Monitor 4 months ago

    Ideally, a split core CT and voltage reference can be used with makes connecting a whole lot easier. looks like they have done a pretty good job with this. I just wanted something simpler, more accurate (split core CTs introduce a number of errors) and with a better database.

    In terms of compression, the algorithm described at (scroll down to the pictures) is even better than a simple deadband filter. I should probably implement something like this, but will probably only get around to it with the SD card fills up.

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