@MattFox Fair enough- @nino-kurtalj said "Let's assume I have values in the W.".. Which I understood to mean he was using "watts" and it looks like he was trying to integrate watts over seconds in the metapoint he posted, using the now-last values as a sort of way to integrate watts into kwh.
Also; @nino-kurtalj if you are integrating watts over time to get kwh, realize that you're accumulating errors as you go. It's much much better to use the raw kwh (or wh, or energy point) out of your metering device. This is because even integrated watts to kwh in mango, you're still limited by polling rate of your device. I run 1000's of points of energy and power in my system, and we can see the errors building up over time: Particularly when the power signal changes rapidly.
The internal power meter kwh points (the "kwh" register you read out of your electrical meter) integrates at "electrical speed", so they catch those wiggles in real time: They basically sum every update of some high-speed V*A calculation.
If you're reading watts and integrating that into wh youself, you can only get those values every time you ask the meter for it, so you'll miss the little wiggles that happen in between polls. If you're polling every second, this will probably be a fairly small error, but it grows over time, so if you go true up your integrated watt -> kwh point by comparing it to like the power company's billing meter, you'll always be off by a few percent. The slower the watt polling interval, the larger that energy error is at the end of the month.
I run into this (and deal with this) all the time in the business I'm in, since some people insist on taking (for example) 15-minute average kilowatt, summing them up, calling it kwh, and then complaining to me that my energy points are wrong- They aren't.
They're just integrating a low-frequency discrete time signal and comparing it with an integral at real time as the signal changes: They will not be the same. That error can cause lots of confusion, if you're (for example) trying to calculate your AC line losses over time- The error in going from 15-minute average power into kwh is generally larger than the actual losses in the cable you're trying to measure.
We do use "integrated watts" from Mango for certain applications, but it's in places where that error is easy to deal with (such as by hourly comparisons, where you don't have time for that error to accumulate over months before comparing).
