Loop Disconnection Detection Judgment Time (Buffer Memory Address: 3B , 5B , 7B , 9B ); Loop Disconnection Detection Dead Band (Buffer Memory Address: 3C , 5C , 7C , 9C ) - Mitsubishi Electric MELSEC Q Series User Manual

3 SPECIFICATIONS
3.5.31 Loop disconnection detection judgment time
(buffer memory address: 3B
3.5.32 Loop disconnection detection dead band
(buffer memory address: 3C
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(1) The loop disconnection detection function detects errors in the control system due
to a load disconnection, external operation device fault, sensor disconnection and
the like.
No temperature change of greater than 2°C (2°F) within the loop disconnection
detection judgment time is judged as a loop disconnection.
(2) As the loop disconnection detection judgment time, set a value longer than the
time taken to vary the temperature 2°C (2°F).
(3) Performing auto tuning automatically sets a value twice longer than the integral
time as the loop disconnection detection judgment time.
However, if the loop disconnection detection judgment time was set to 0 at the
auto tuning, the loop disconnection detection judgment time is not stored.
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(1) To prevent the false alarm of loop disconnection detection, set the non-alarm area
(temperature width where loop disconnection will not be detected) around the set
value.
Process value (PV)
Set value (SV)
(2) The setting range is within the temperature setting range specified in the Input
range (buffer memory address: 20
For example, if Loop disconnection detection dead band (buffer memory address:
3C , 5C , 7C
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detection judgment is not made within the set value range of 5.0°C.
(3) The set value varies with the setting increments of Input range (buffer memory
address: 20 , 40
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• If the setting increments(1) without a decimal point is set, the value is set in
increments of 1 degree Celsius.
• If the setting increments(0.1) with a decimal point is set, the value is set in
increments of 0.1 degree Celsius. (The value is indicated without a decimal
point.)
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, 5B , 7B , 9B )
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, 5C , 7C , 9C )
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Non-alarm area
, 40 , 60
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, 9C ) is "50" at the input range setting of 38, loop disconnection
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, 60 , 80 )(refer to Section 3.5.12) as indicated below:
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MELSEC-Q
Loop disconnection detection
dead band setting
Time
, 80 ) (refer to Section 3.5.12).
H H
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