Hioki SW1001, Инструкция по эксплуатации

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35
Precautions for Measurement
3.6 Precautions for Measurement
Use in combination with BT3562 or BT3563
Contact check does not operate properly at 3000
Ω
range. Also be aware that contact check cannot
be performed properly in the voltage function, either.
Use in combination with BT4560
Use the device with BT4560 for external trigger measurement or single measurement using the
:READ?
command.
When using the device for internal trigger (free running), the life time of the relay is shortened as
the channel is switched during measurement (hot switching).
As the measurement current for BT4560 is 1.5 A (3 m
Ω
range), heat generation at the relay contact
becomes high. With heat generation, the thermoelectric power may become high.
Use in combination with DM7275 or DM7276
If a measurement accuracy of a few µV is required, there is an effect by the thermoelectric power
due to coil heating of the channel relay. Minimize the close time of each channel to reduce this
effect as much as possible. Use single measurement using the
:READ?
command or external
trigger and open the channel immediately after the measurement (heating from the relay coil is
controlled).
Measured value variation may be significant when connected at the same time as the IM3590.
If you encounter this issue, enable the IM3590’s trigger synchronous output function.
Use in combination with IM3590
Execute open correction and short correction to each channel you will use.
Error might occur to open correction and short correction due to high frequency. (Set the frequency
range you will correct when executing.)
Threshold value of the contact check might be larger than the setting.
Also, the inspection result of the contact state (the resistance value near the threshold) might vary.
Relay operation time and stability time
The relay open/close operation waits for a contact operation time (settling time). The settling time is
as follows.
Channel switching time
Relay open settling time Relay close settling time
Settling time
Relay open Relay close Channel switching
5 ms 5 ms 11 ms
The relay contact operation is completed within the settling time, however, it may take some time
for the relay to be stabilized depending on the instrument to be used or measuring object. Set the
channel delay time or perform measurement after a sufficient delay time on the instrument.
Preventing relay contact welding
The relay contact may weld when relay switching is repeated with a large current flowing (also
when the measuring object or instrument to be connected is capacitive). When relay contact
welding occurs, the measuring object may be shorted. Periodic inspection is recommended.
Reference: "Checking for relay contact welding" (p. 26)
3
Channel Switching