3.4 Checking Measured Values
39
3
*1 Over-range Detection Function
Examples of Over-range Faults
*2 Current Fault Detection Function
Example of Current Fault
• SOURCE A or SOURCE B probe open
• Broken measurement target (open work)
• SOURCE A or SOURCE B cable break, poor connection
• SOURCE wiring resistance in excess of the following values may cause a current fault,
making measurement impossible. When using measurement current 300 mA ranges,
keep the wiring resistance as well as the contact resistance between the measurement
target and measurement lead low.
• If a measurement is performed using a high-resistance range, it will take time after the
probes are actually open until a constant current error occurs.
Example:300 k range 20 ms
3 M range 250 ms
Over-range Detection Measurement Example
The measured value is outside of
the measurement range.
Attempting to measure 40 m with the 30 m range selected
The relative tolerance (%) display
of the measured value exceeds
the display range (999.99%).
Measuring 500 (+2400%) with a reference value of 20
The zero-adjusted value is out-
side of the display range.
Performing zero-adjustment after connecting 50 m with the 300 m
range
Measuring 10 m yields a -40 m reading, exceeding the display
range.
While measuring, input voltage
exceed the A/D converter input
range.
Measuring a large resistance value in an electrically noisy environment
Current did not flow normally to
the measurement target.
(When the current fault mode set-
ting is set to “Over-range output”
only)
When the measurement target yields an open FAIL result
When either the SOURCE A or SOURCE B terminal suffers from poor
contact.
*To display “- - - - -” when a current fault occurs, set the current fault
mode setting to “Current fault.”(p.40)
(Reference value)
Range
Wiring resistance and contact resistance
(Resistance value between SOURCE B and SOURCE A,
excluding measurement target)
30 m, 300 m 2
3 70
30 100
300 2 k
3 k 700
30 k to 3 M 2 k
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