3-16
IM 253710-01E
Note
•
Check that the power measurement modules are installed in order starting from the element
number 1 slot. If you leave the slots that have smaller element numbers empty,
measurements will not be made properly. (For example, do not install a power measurement
module into the element number 2 slot and leave the element number 1 slot empty. Do not
install power measurement modules into element number 1 and 3 slots and leave the element
number 2 slot empty.) For the procedures on installing the modules, see section 3.3,
“Installing the Input Module.”
•
When the sensor input module is installed into the element number 4 slot, only up to three
power measurement modules can be installed. In this case, you cannot select a wiring
method that uses four power measurement modules.
•
After wiring, the wiring method must be selected. See section 5.2, “Selecting the Wiring
Method.”
•
The thick lines on the wiring diagrams are the sections where the current flows. Use
appropriate wires that are suitable for the current.
•
The current sensor input transformation function can be used to transform the input signal to
data that correspond to direct measurements. For the procedures, see section 5.4, “Setting
the Measurement Range when using an External Current Sensor.”
•
Note that the frequency and phase characteristics of the external current sensor affect the
measured data.
•
Make sure that the polarity is correct when connecting to the circuit. Otherwise, the polarity of
the measured current is reversed and proper measurements cannot be made. Be especially
careful when using a clamp-type current sensor, because it is easy to reverse the connection.
•
To minimize error when using a shunt-type sensor, note the following points when connecting
the external sensor cable.
•
Connect the shielded wire of the external sensor cable to the L side of the shunt output
terminal (OUT).
•
Minimize the area created between the wires connecting the current sensor to the external
sensor cable. The effects due to the line of magnetic force and noise that enter this area
of space can be reduced.
Shunt-type current sensor
I
±
OUT H
OUT L
Shielded wire
External sensor cable
PZ4000
Area of space created by the connection wires
•
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
±
Current sensor input connector
Voltage input terminal
•
When the circuit under measurement is not grounded and the signal is high in frequency or
large in power, the effects of the inductance of the connection cable for the shunt-type current
sensor become large. In these cases, use an isolation sensor (CT, DC-CT, or clamp) for the
measurements.
LOAD
Clamp-type current sensor
V
±
Voltage input terminal
Current sensor input connector
3.8 Using an External Current Sensor to Wire the Circuit under Measurement