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IM WT1801-01EN
Phase Difference Display Format (Phase)
The phase difference Φ between the voltage and current indicates the current phase relative to the voltage of
each element. Set the display format to one of the options below.
• 180 degrees
If the current phase is in the counterclockwise direction with respect to voltage, the current is leading (D) the
voltage. If the current phase is in the clockwise direction with respect to the voltage, the current is lagging
(G) the voltage. The phase difference is expressed by an angle between 0 and 180° (see appendix 2 in the
getting started guide, IM WT1801-03EN).
• 360 degrees
The phase difference is expressed as an angle between 0 and 360° in the clockwise direction.
• If the measured voltage or current value is zero, “Error” is displayed.
• When both the voltage and current signals are sinusoidal waves and the ratios of the voltage and current
inputs with respect to the measurement range do not differ greatly, the phase difference Φ lead and lag are
still detected and displayed correctly.
• If the computation result of power factor λ exceeds 1, Φ is displayed as follows:
• If the power factor λ is greater than 1 and less than or equal to 2, Φ returns 0.
• If λ is greater than 2, Φ returns an error (“Error” is displayed).
• On models with the harmonic measurement option, the phase differences ΦU and ΦI of harmonic orders
1 to 500 of the voltage and current are always displayed using an angle between 0 and 180° (no sign for
lead and negative sign for lag).
Master/Slave Synchronization Measurement (Sync Measure)
Connect the external start signal input/output connectors (MEAS. START) of the master and slave instruments
using a BNC cable (sold separately). You can synchronize the measurement of two WT1800s making one
WT1800 the master and the other WT1800 the slave. The master outputs a measurement start signal, and the
slave receives the signal.
For the specifications of the external start signal input/output connectors, see section 4.4 in the getting started
guide, IM WT1801-03EN.
The measurement of the master and slave cannot be synchronized under the following conditions:
• When the data update interval differs between the master and slave.
• During real-time integration mode or real-time storage mode.
Follow the procedure below to hold the display during synchronized measurement.
• To hold the display: Hold the display of the master first.
• To unhold the display: Unhold the display of the slave first.
8 Computation