METREL MI 2893 - 5 Theory and internal operation; 5.1 Measurement methods

MI 2893 / MI 2892 / MI 2885 Theory and internal operation
179
DC
Fundamental
Nonfundament.
Active Energy
Reactive Ener.
Power factors
Legend:
 - Quantity included.
- Maximal value for each interval is recorded.
- RMS or arithmetic average for each interval is recorded (see 5.1.15 for details).
- Minimal value for each interval is recorded.
- Active RMS or arithmetic average (AvgON) for each interval is recorded (see 5.1.15 for details).
5 Theory and internal operation
This section contains basic theory of measuring functions and technical information of the internal
operation of the MI 2893/MI 2892/MI 2885 instrument, including descriptions of measuring methods
and logging principles.
5.1 Measurement methods
5.1.1 Measurement aggregation over time intervals
Standard compliance: IEC 61000-4-30 Class A (Section 4.4)
The basic measurement time interval for:
 Voltage
 Current
 Power
 Harmonics
 Inter-harmonics
 Signalling
 Unbalance
is a 10/12-cycle time interval. The 10/12-cycle measurement is resynchronized on each Interval tick
according to the IEC 61000-4-30 Class A. Measurement methods are based on the digital sampling of the
input signals, synchronised to the fundamental frequency. Each input (4 voltages and 4 currents) is
simultaneously sampled.
5.1.2 Voltage measurement (magnitude of supply voltage)
Standard compliance: IEC 61000-4-30 Class A (Section 5.2)