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IM WT1801-01EN
External Current Sensor Range Display Format (DIRECT/
MEASURE; option)
You can select the external current sensor range display format from the following options.
• DIRECT (direct input value display)
Values are displayed within the external current sensor range (voltage). This setting is useful when you want
to set the external current sensor range using the voltage received by the WT1800 from the external current
sensor as a guide.
• MEASURE (measurement range display)
The external current sensor range is divided by the external current sensor conversion ratio, and the resulting
(current) range is displayed. This setting is useful when you want to set the external current sensor range
using the current measured by the external current sensor as a guide. For example, if you are using a current
sensor that produces 10 mV when it receives 1 A (external current sensor conversion ratio: 10 mV/A) and you
set the external current sensor range to 1 V, the displayed current range is 100 A.
Scaling (SCALING)
You can set coefficients for when you apply a voltage or current signal from an external VT (voltage transformer)
or CT (current transformer).
Turning Scaling On and Off (Scaling)
You can select whether to apply the VT ratio, CT ratio, and power coefficient to applicable measurement
functions.
When reading measured values directly by using a VT or CT (or current sensor), select ON. When you select
ON, the SCALING key and the Scaling indicator at the top of the screen illuminate.
Applicable Measurement Functions
Voltage (U), current (I), power (P, S, and Q), maximum and minimum voltages (U+pk and U-pk), and maximum
and minimum currents (I+pk and I-pk)
• ON: The measurement functions above are multiplied by the VT ratio, CT ratio, or power coefficient.
• OFF: The measurement functions above are not multiplied by the VT ratio, CT ratio, or power coefficient. The
output values of the VT and CT are displayed directly as numeric data.
VT Ratio (VT Scaling)
Set the VT ratio when applying the secondary output of a VT to the voltage input terminal. Then, set the voltage
range according to the maximum VT output.
Element1 to Element6
Use the soft keys to select an element, and then set the element’s VT ratio to a value within the following range.
0.0001 to 99999.9999
Copying the VT Ratio (Exec Copy Σ)
Copy the VT ratio of the selected input element to the other input elements in the same wiring unit.
CT Ratio (CT Scaling)
Set the CT ratio (or the conversion ratio of the current sensor that produces current) when applying the
secondary output of a CT or clamp-type current sensor that produces current to the current input terminal. Then,
set the current range according to the maximum CT or current sensor output.
Element1 to Element6
Use the soft keys to select an element, and then set the element’s CT ratio to a value within the following range.
0.0001 to 99999.9999
Copying the CT Ratio (Exec Copy Σ)
Copy the CT ratio of the selected input element to the other input elements in the same wiring unit.
2 Fundamental Measurement Conditions
