EmonLibPro - Continuous sampling, Multi sensor, Interrupt based

Continue discussions from : EmonLibPro Released - Continuous sampling, Multi sensor, Interrupt based, implements a zero cross detector and PLL. | Archived Forum

Ulli 16/05/2016 - 08:41
I have a voltage measurement just at L1 but I want to measure 3 phase currents. Is it possible to shift the measured power by 120deg? or is there a EmonLibPro for continuous sampling 3 phase currents?

chaveiro 16/05/2016 - 17:08
You can measure 2-3 phases but only reference it to one voltage sensor.
Adjust the current phase with the CalCoeff variable. With a known constant current setup match the variables so the readings from the lib are close to real.

Ulli 17/05/2016 - 08:41
thanks! But I do.not really understand the calculation basis.
e.g. 20076 for CT2 whats behind that value?

Additionally when I want to shift the current phase is it sufficient to add cos(120deg)?

chaveiro 17/05/2016 - 17:36

This is a little obscure, but read additional details on this doc:

Chapter 3.8.1.

I checked the Chapter 3.81 in the document but I do not understand how to shift the phase by 120deg.
PCC is the calibration factor we want to calculate.
fm is 50Hz and fclk is 16Mhz
Z is the phase shift

You defined the following:
CT1: 20076 → 1,720°
CT2: 40152 → 1,720°x2
CT3: 60228 → 1,720°x3

Therefore I just need to add 120°, right.
CT1: 20076 → 1,720°
CT2: 1420418 → 120° + 1,720°
CT3: 2820760 → 120°*2+1,720°
But these values are to big, aren’t they? The Range is 0 to 65535