Wiring The Measurement Circuit When Using The External Sensor - YOKOGAWA WT200 User Manual

3.8 Wiring the Measurement Circuit when Using
the External Sensor
3-10
• Use an external sensor that is enclosed in a case which has sufficient withstand
voltage against the voltages to be measured. Use of bare sensor may cause an
electric shock if the sensor is touched accidentally.
• Before connecting an external shunt, make sure the power to the shunt is turned
OFF. Always make sure to turn OFF the power switch of the source.
When the power is supplied a voltage will be present at the shunt, so don't touch
the shunt with your hands.
• When using the clamp sensor, make sure you have a thorough understanding of
the specifications and handling of the voltage of the measurement circuit and
the clamp sensor. Check that there are no hazards (places that may cause
electric shock).
• When using the external sensor input terminal, do not touch the current input
terminal or connect measurement leads. This act is dangerous, because when
power is applied to the circuit under measurement (that is connected to the
external sensor input terminal), the voltage of the circuit appears across the
current input terminals.
• The connector to the input terminal for the external sensor should not have bare
wires protruding; make sure to make connections to this terminal according to
safety measures, since voltages will be present at the bare wires, which
constitutes a hazard.
A load current flow in the thick lines shown in the diagrams; therefore, a
wire with sufficient current capacity must be used for these lines.
In cases where the maximum current of the object under measurement exceeds 20 A,
measurement becomes possible by connecting an external sensor. The range for
external sensor input is either 2.5/5/10 V or 50/100/200 mV. Either range is available as
an option.
In the following wiring diagrams, the external shunt is grounded. When using the clamp
sensor, replace the shunt with the clamp sensor.
Wiring diagram when using the external shunt
SOURCE
Shunt-type current
sensor
±
Connection
side
OUT L
Ext. sensor input
terminal (EXT)
WARNING
CAUTION
LOAD
A
OUT H
±
V
A
±
Input terminal
(ELEMENT)
IM 253421-01E