Hi all

I have a Emontx V2 and a rasperry pi base station. I have 1 CT bought here and 1 other, smaller, CT bought elsewhere.

I've done some testings with some incadescent lights and  a power meter bought a few years ago.

With this setup i was able to calibrate the 3 CT without problem and even got the emonbase to receive the results.

Now i moved to a more real test. I plugged  one CT to a TV, the other to a cable box and the other to the junction box where the TV and cable go. My goal was to measure the total power and how much the TV and cable box was using.

But when i got the readings, they were all wrong. The one where it should give the total power is giving me a lower value than the TV for instance.

Do i need to calibrate again? Why



Robert Wall's picture

Re: Calibration

It is impossible to know what is happening without some numbers. Have you read in Building Blocks about measurement accuracy, for example? If you are trying to read currents that are very small relative to the maximum possible current (and that would be likely given the nature of the load), then you can never expect accurate measurements.

There's also a FAQ about this.

pb66's picture

Re: Calibration

Just checking.... Are you definitely only putting the ct around a single core rather than "the power cable" set of (2 or) 3 individual cores? To monitor each consumer that way will require some form of custom breakout box (or exposed section of "the power cable") to get access to single cores.


[See "C.T. Sensors - installation" in Building Blocks - (RW)]

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