Instruction manual

7. FUNCTIONS
IMSRM15-E6
125
LBA deadband (LBD)
The LBA may be produced by disturbances (other heat sources) even if the control system is not
abnormal. In such a case, an area in which no alarm is produced can be set by setting the desired LBA
deadband (LBD).
When the measured value (PV) is within the LBD area, no alarm is produced even if all of the
conditions to produce the alarm are satisfied. Therefore, carefully set the LBD.
The LBA function detects an error occurring in the control loop, but cannot specify the
erroneous location. Therefore, check the control loop in order.
The LBA function is not activated when any of the following cases occurs.
When the autotuning function is being executed.
When operation mode is not in Normal mode.
When the LBA setting time is extremely short or does not meet the controlled object, the
LBA may be turned on and off, or may not be turned on. In such a case, change the LBA
setting time depending on the situation.
The LBA output is turned off when any of the following cases occurs with the LBA output
turned on.
When the measured value (PV) rises beyond (or falls below) the LBA triggering width
within the LBA setting time.
When the measured value (PV) is within the LBA deadband.
A: During temperature rise: Alarm area During temperature fall: Non-alarm area
B: During temperature rise: Non-alarm area During temperature fall: Alarm area
LBD differential gap
Alarm area
Non-alarm area
Set value (SV) LBD set value
Low High
A B Alarm area