I'm using the JSON interface to read real-time values from the FLM for a pulsed watthour meter.
The meter generates 1600 pulses per kWh -- 1.6 pulses per Wh -- 0.625 Wh per pulse.
It's pulsing now at a rate of about once every three seconds. That's about 0.21 Wh per second, or 750 Wh per hour, or 750 W. The load is relatively constant. Not exactly, but no large variations. I am independently measuring the load with another meter that's reporting 705W -- fairly close.
The JSON API is returning 584 W for 13 seconds, then 1172 W for 3 seconds, then repeats. The last 2 to 5 fields in the returned JSON array are "nan". The nan timeslots appear to be regularly updated within a few seconds, all with the same value.
I can deal with the nan's. The bigger problem is the 2:1 variations in reported power.
Any idea why this is happening? How and when are those numbers calculated? I could understand if they were only updated when a new pulse arrives, but that should be once every three seconds, not 3 then 13. What's worse is that neither reported value is correct.
If I average the values over the 3+13 second range (694 W), that looks about right. I guess averaging is a workaround for now, but it also means the data won't be as "real-time" as I'd like it to be.