YOKOGAWA WT210, User Manual, Page: 65 / 316

3-16
IM 760401-01E
• For a shunt-type current sensor, connect it to the power earth ground side as shown in the
figure below. If you have to connect the sensor to the non-earth side, use a wire that is
thicker than AWG18 (conductive cross-sectional area of approx. 1 mm
2
) between the sensor
and the instrument to reduce the effects of common mode voltage. Take safety and error
reduction in consideration when constructing an external sensor cable.
LOAD
Shunt-type current sensor
V
±
External sensor input
connector (EXT)
Voltage input terminal
• If the measurement circuit is not grounded and the measured signal is of high frequency or
high power, the effects of inductance of the shunt-type current sensor cable become large. In
this case, use an isolation sensor (CT, DC-CT, or clamp).
LOAD
Clamp-type current sensor
V
±
Voltage input terminal
External sensor input
connector (EXT)
• Make sure you have the polarities correct when making the connections. Otherwise, the
polarity of the measurement current will be reversed and correct measurements cannot be
made. Be especially careful when connecting the clamp type current sensor, because it is
easy to reverse the connection.
• You can use the scaling function to directly read the measured values on the display. For the
procedure, see section 4.6, “Selecting the Measurement Range and Setting the Scaling Value
when External Sensor is Used (option).”
• For the relationship between the wiring systems and the method of determining the measured
values or computed values, see page 16-6.
3.9 Using an External Sensor to Wire the Circuit under Measurement