YOKOGAWA CW140, User Manual, Page: 21 / 292

2-7
IM CW140-E
Product Overview
2
2.4 Overrange and Other Marks Shown during Measurement
CAUTION
When measuring an input signal level exceeding the rated range, use a voltage transformer (VT)
or a current transformer (CT) - scaling function. When using a VT or CT, thoroughly read Section
3.5, "Wiring the Circuit under Test Using External VT/CT."
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Frequency-related Overrange Indications
Normal measurement: The measurement range is from 45 Hz to 1 kHz.
The display shows "----" if the input signal is below 40 Hz or above 1.2 kHz.
Three-phase unbalance factor measurement:
The measurement range is from 45 to 440 Hz.
The display shows "----" if the input signal is below 40 Hz or above 440 Hz.
Harmonics measurement: The measurement range is from 45 to 65 Hz.
The display shows "----" if the input signal is below 40 Hz or above 70 Hz.
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Indications When the Measured Value Is Too Small
If either a voltage or current input level is below 0.4% of the rated range, the
CW140 gives the readings noted below. If a fixed range is used, step down
the range.
Reactive power 2 and apparent power: Read zero (0).
Power factor and phase angle: Read as "----".
If the level of active power or reactive power is below 0.7% of the rating, the
reading is displayed as shown below.
Active power or reactive power: Read zero (0). The integration stops.
In harmonics measurement, the display reads as shown below if the input
level of a frequency-measuring device is below 10% of the rated range.
All measurement data items: Read as "----".
If the voltage, current or power harmonic content in harmonics measurement
is below 0.1%, the phase angle of a harmonic component of that order reads
as "----".
TIP
Even if the instantaneous value overrange occurs and the OR symbol appears in the electric energy
measure mode, the integration processing continues. In this case, the level of accuracy of the on-screen
integrated value may become inaccurate (about two times) that of the rated accuracy.
NOTE
If continuous measurement (logging, integration, or demand) is performed when in AUTO range,
the range will be fixed to the value when the START&STOP key is pressed.