Mitsubishi Electric MELSEC FX2N-2LC, User Manual

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FX2N-2LC Temperature Control Block Buffer Memory (BFM) 7
7-21
7
7.2.32 In BFM #50, set the loop breaking alarm dead zone of CH1.
In BFM #69, set the loop breaking alarm dead zone of CH2.
The loop breaking alarm function may issue alarms caused by disturbances (effect of another
heat source, etc.) even if there is no abnormality in the control system. In order to prevent
such alarms, by setting the loop breaking alarm dead zone, the region in which the alarm func-
tion is disabled (non-alarm status region) can be set.
For example, if the loop breaking alarm dead zone is set to "10
°
C", 10
°
C above the set value
(SV) and 10
°
C below the set value (SV) are treated as the non-alarm status region (width of 20
°
C in total).
While the measured value (PV) is located within the non-alarm region, alarm is not issued
even if the alarm condition is satisfied.
The allowable set range is form 0.0 (or 0) to the input range span (
°
C or
°
F).
When BFM #50 / #69 is set to "0", the loop breaking alarm dead zone function is disabled.
*1 While the temperature is rising: Alarm status region
While the temperature is decreasing: Non-alarm status region
*2 While the temperature is rising: Non-alarm status region
While the temperature is decreasing: Alarm status region
*3 LBD operation gap (0.01%FS)
Alarm status region Alarm status region
LBD operation gap *3
LBD operation gap *3
Non-alarm status region
Low High Temperature set value (SV) LBD set value
*1
*2