2-19
IM WT1801-01EN
• If you specify no sync source by selecting “None,” all of the sampled data within the data update interval
is used to determine the numeric data. When you are measuring DC signals, this method can be used to
prevent noise from causing errors in the detection of the measurement period.
• If the sync source is not set correctly, the measured value may fluctuate or be incorrect. When you set the
sync source, refer to appendix 5 in the getting started guide, IM WT1801-03EN.
Line Filter (LINE FILTER)
There are two types of input filters, line filters and frequency filters.
Because the line filter is inserted into the voltage and current measurement input circuits, it directly affects
voltage, current, and power measurements (see the block diagram in appendix 11 in the getting started guide, IM
WT1801-03EN). When the line filter is turned on, measured values do not contain high frequency components.
Thus, the voltage, current, and power of inverter waveforms, strain waveforms, etc., can be measured with their
high frequency components eliminated.
Element1 to Element6
Use the soft keys to select an element, and then turn the line filter on or off, and set the cutoff frequency.
You can set the cutoff frequency to
300 kHz, 1 MHz, or a value from 0.1 kHz to 100.0 kHz (in 0.1 kHz steps)
• If the line filter of even one of the elements is not set to OFF, the LINE FILTER key and the Line Filter indicator
at the top of the screen illuminate.
• Selecting OFF disables the line filter.
Copying the Line Filter Setting (Exec Copy Σ)
Copy the line filter on/off setting and cutoff frequency of the selected input element to the other input elements in
the same wiring unit.
Line Filter for High Speed Data Capturing
Frequency Filter (FREQ FILTER)
The frequency filter is inserted into the frequency measurement input circuit and affects frequency
measurements. It also affects the detection of the measurement period for voltage, current, and power
measurements (see appendix 5 in the getting started guide, IM WT1801-03EN). In this case, the filter also acts
as a filter for detecting the
of the synchronization source signal more accurately. The frequency
filter is not inserted into the voltage and current measurement input circuits. Therefore, the measured values
include high frequency components even when the frequency filter is turned on.
Element1 to Element6
Use the soft keys to select an element, and then select the element’s cutoff frequency from the options listed
below.
OFF, 100 Hz, and 1 kHz
• The WT1800 detects the zero-crossing point with a hysteresis of approximately 5% of the measurement
range.
• If even one element is not set to OFF, the Freq Filter indicator at the top of the screen illuminates.
• If the line filter described above is on, it affects the frequency measurement even when the frequency filter is
off.
• We recommend that you turn the frequency filter on when the input signal frequency is less than or equal to
440 Hz.
2 Fundamental Measurement Conditions
