i've been using the emonTX v3.4 for 4 weeks now and i must say i'm very impressed.
as part of some internal energy audit i'm doing at home, i also wanted to know what my power factor is and the line frequency.
this "new" Discrete Sampling sketch includes, beside the standard items also the power factor for CT1..4 and line frequency as measured during EnergyMonitor::calcVI() step. For this i extended emonLib to calculate the frequency while sampling the data. The time measurement is based on arduino micros() and should have a accurancy around +/- 4...5 usec which should be enough for 50Hz measurements. a drop of 50Hz -> 49 Hz is around 408 usec per cycle, the sketch samples for 15 full cycles, so see a time difference of +/- 6120 usec for 1 Hz drop .
A updated emonhub configuration is included, and result can be seen at this URL
http://emoncms.org/dashboard/view?id=30272
The frequency graph still need some low pass filtering like moving average of N samples to make it more clear. The frequency was added to "try" to see some case where power grid is "high" loaded, as this would cause a long time small drop of 0.5 .. 1 Hz in the frequency.
For the first week i see a very stable 50.05 .. 49.95 Hz frequency, but that was expected because our power grid in Belgium have all there nuclear plants running again after a period of 2 years of troubles , causing a export of power instead of power shortage.
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Submitted by luc.willems@it4y.eu on Sun, 17/01/2016 - 10:42Hi All ,
i've been using the emonTX v3.4 for 4 weeks now and i must say i'm very impressed.
as part of some internal energy audit i'm doing at home, i also wanted to know what my power factor is and the line frequency.
The result is an updated emonTxV3_4_DiscreteSampling_Full you can find on
https://github.com/lucwillems/emonTxFirmware/tree/master/emonTxV3/RFM/em...
this "new" Discrete Sampling sketch includes, beside the standard items also the power factor for CT1..4 and line frequency as measured during EnergyMonitor::calcVI() step. For this i extended emonLib to calculate the frequency while sampling the data. The time measurement is based on arduino micros() and should have a accurancy around +/- 4...5 usec which should be enough for 50Hz measurements. a drop of 50Hz -> 49 Hz is around 408 usec per cycle, the sketch samples for 15 full cycles, so see a time difference of +/- 6120 usec for 1 Hz drop .
A updated emonhub configuration is included, and result can be seen at this URL
http://emoncms.org/dashboard/view?id=30272
The frequency graph still need some low pass filtering like moving average of N samples to make it more clear. The frequency was added to "try" to see some case where power grid is "high" loaded, as this would cause a long time small drop of 0.5 .. 1 Hz in the frequency.
For the first week i see a very stable 50.05 .. 49.95 Hz frequency, but that was expected because our power grid in Belgium have all there nuclear plants running again after a period of 2 years of troubles , causing a export of power instead of power shortage.