Effective power measurement

The EL34x3 measures the effective power P according to the following equation

P: Active power
n: Number of samples
u_(t): Instantaneous voltage value
i_(t): instantaneous current value

In the first step, the power s_(t) is calculated at each sampling instant:

The mean value over the measuring interval is calculated. Here too, the correct choice of the intervals is important, as described in section RMS value measurement (the interval can only be changed simultaneously for U, I and P).

The power frequency is twice that of the corresponding voltages and currents.