Data is received with a Moteino I wrote about in an earlier post. RFM69Pi implementation using a Moteino - #7 by kobuki
I filter lines printed on the serial line whose first word is “OK” and use simple shell arithmetics to post data using a Zabbix utility. These are among the the tools I use regularly so I know them pretty well. I don’t suspect faults here. But it’s for some tests only.
The fluctuation was modulated on a base power of around 6-700W so pretty significant. It sometimes stopped appearing for 5-10 cycles and during these periods it showed very little changes per measurement (I’d say “normal”). Again - the only thing I did was changing the position of the CT from the bottom of the U shape to the (left) side where it’s more or less straight, then watched the power curve. I can only think of some peculiar wire arrangement in the box above the test hook that influences measurements when the CT is placed in certain positions… I’m now using simple cloth clips for holding the CTs on the side to avoid future problems.
Attached are 2 chart images around the problematic part. On the first image you can see the state before and after playing around with the CT, arranging things, etc. On the second you can see the state after the problem with more details. After the spike on the right the CT has been positionied on the wire as I described above.
There’s another weird thing on the first image. That large ~2.5 kW streak on the left is after the rearrangement of the CTs. It didn’t really exist as consumed power. It disappeared after a reset of the EmonTX (unplug-replug). I credited it to the several changes I made and ignored it.
