CS5461A datasheet(14/44 Pages) CIRRUS

14 / 44 page

CS5461A

DS661F2

To generate a value for the accumulated active energy

over the last computation cycle, the active power can be

multiplied by the time duration of the computation cycle.

The apparent power is the combination of the active

power and reactive power, without reference to an im-

pedance phase angle, and is calculated by the

CS5461A using the following formula:

The apparent power is registered once every computa-

tion cycle.

4.4 Linearity Performance

The linearity of the VRMS, IRMS, and active power mea-

surements (before calibration) will be within ±0.1% of

reading over the ranges specified, with respect to the in-

put voltage levels required to cause full-scale readings

in the IRMS and VRMS registers. Refer to Linearity Per-

formance Specifications on page 7.

Until the CS5461A is calibrated, the accuracy of the

CS5461A (with respect to a reference line-voltage and

line-current level on the power mains) is not guaranteed

to within ±0.1%. See Section 7. System Calibration on

page 35. The accuracy of the internal calculations can

often be improved by selecting a value for the Cycle

Count Register that will cause the time duration of one

computation cycle to be equal to (or very close to) a

whole-number of power-line cycles (and N must be

greater than or equal to 4000).

RMS

CS5461A Datasheet(PDF) 14 Page - Cirrus Logic