3-7
IM 253710-01E
Before Starting Measurements
3
• When using a clamp-type current sensor as an external current sensor, have a
good understanding of the voltage of the circuit under measurement and the
specifications and handling of the clamp-type sensor. Then, confirm that there
are no shock hazards.
• For safety reasons, when using the instrument on a rack mount, furnish a switch
for turning OFF the circuit under measurement from the front side of the rack.
• To make the protective functions effective, check the following items before
applying the voltage or current of the circuit under measurement.
• The power cable provided with the instrument is used to connect to the power
supply and the instrument is grounded.
• The power switch of the instrument is turned ON.
• The current input protective cover provided with the instrument is being used.
• When the power switch of the instrument is turned ON, do not apply a signal
that exceeds the following values to the voltage or current input terminals.
When the instrument is turned OFF, turn OFF the circuit under measurement.
For other input terminals, see the specifications of each module in chapter 17.
Max. Allowable Input Voltage Input
Current Input
Instantaneous max.
The peak value is 2000 5 A terminal : The peak value is 30 A or the
(1 second)
V or the RMS value is
RMS value is 15 A, which ever
1000 V, which ever is
is less.
less. (CAT II)
20 A terminal : The peak value is 150 A or the
RMS value is 40 A, which ever
is less.
Continuous max.
Same as the
5 A terminal : The peak value is 10 A or the
“Instantaneous max.”
RMS value is 7 A, which ever is
shown above.
less.
20 A terminal : The peak value is 100 A or the
RMS value is 30 A, which ever
is less.
CAUTION
Use measurement cables that have adequate margins of withstand voltage and
current capacity with respect to the voltage or current being measured. It should
also have proper ratings that are suited to the measurement.
Example : When making measurements on a current of 20 A, use copper wires
that have a conductive cross-sectional area of 4 mm
2
.
Note
•
After wiring, the wiring method must be selected. See section 5.2, “Selecting the Wiring
Method.”
•
When measuring large currents or voltages or currents that contain high frequency
components, take special care in dealing with mutual interference and noise when wiring.
•
Keep the measurement cables as short as possible to minimize the loss between the circuit
under measurement and the instrument.
•
The thick lines on the wiring diagrams shown in sections 3.7 and 3.10 are the sections where
the current flows. Use appropriate wires that are suitable for the current.
•
In order to make accurate measurements of the voltage of the circuit under measurement,
connect the cable to the circuit as close as possible.
•
In order to make correct measurements, separate the measurement cables as far away from
the earth ground wires and the instrument’s case as possible to minimize the static
capacitance to earth ground.
3.4 Wiring Precautions
