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Logging ac Voltage (2 phase system)

Hi,
a bit lost!

I am trying to log the voltage on both phases (separately). It will be a voltage around 240v (ie 238>245), so I would like to log the values.
The reason for this is so I know when we lose the grid supply (which could drop on either phase, but most likely both together). This will let me track the times my battery actually performs the grid backup function (that could be 4-5 times a year). Also I can track the actual supply voltage.
Here in Australia, the suppliers tend to keep the voltage high, because the power consumption then increases. We have issues with inverters tripping due to over-voltage (not in my case because I use vge control setting on my inverter). Knowing the actual voltage means we can then ask the supply authority to reduce the vge tapping on the transformer (no Solid state smart grid supplies here!)
I will be reading the vge from the IoTaWatt, that I have calibrated using a true RMS meter (accurate enough for my purposes). The data is reaching my local EmonCMS server, but I am unsure how to configure the inputs.

If you don’t have the voltage appearing at an input, it’s really a question for the iotawatt forum, because very few people here know anything about it.

If you do see the two voltages on the Input page (they appear automatically once data is arriving), then you need to set up two Feeds (using the spanner icon to access the input process list setup page).

I’m in the UK, on a single phase supply, so I have


The first process logs to a feed, which is the actual storage mechanism for data. The value falls through to the next step:
The second adds -240 V (the nominal voltage) and passes the result to the 3rd step, which logs that, so I get the difference from the nominal, making it easy to see small changes.

In each case, I did that using the drop-down list under "Add process to specify what process to add, the type of Feed engine (you most likely need PHPFINA if the data comes in regularly) and the name you’ll call the feed and the intervals at which it records the data. It’s offering 10 s here. The text in the blue box is the documentation for the process you’ve selected.

When you’ve done that - probably much the same for both phases - you can see the feeds on the Feeds page, and then plot graphs on the Graphs page, and so on.

I’m sure all this is documented in the Guide. This is the part you probably need: Emoncms Core Concepts - Guide | OpenEnergyMonitor

Thanks. Exactly what I needed. Yesa, the data was available at Emoncms but I was unsure how to treat it.

Help much appreciated, Doug

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