Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 183)

Publication 900-UM007D-EN-E - January 2011
Parameter Adjustments & Application Considerations 4-47
9. Press the O key for at least 1 second to move from the Initial Setting
function group to the Operation function group.
Figure 4.93
Loop Break Alarm Loop Break Alarm (LBA)
With a Loop Break Alarm, there is assumed to be an error in the operation
control loop if the control deviation (SP
− PV) is greater than the threshold
you configure in the LBA Level parameter and if the control deviation is not
reduced by at least the value you configure in the LBA Detection Band
parameter within the LBA Detection Time parameter.
Figure 4.94 provides an example of the operation of the Loop Break Alarm
detection and time operation.
Figure 4.94
If the control deviation is reduced in the area between 1 and 2 (i.e., the set
point is approached) and the amount the control deviation is reduced is at least
equal to the LBA Band, the Loop Break Alarm will remain OFF.
The process value is within the LBA Level between 3 and 4, and thus Loop
Break Alarm will not be detected. (The Loop Break Alarm will remain OFF.)
If the process value is outside the LBA Level between 4 and 5 and the control
deviation is not reduced by at least the LBA Band within the LBA Detection
Time, the Loop Break Alarm will turn ON.
C 25
100
PV/SP
LBA ON LBA ON LBA OFF LBA OFF
(1)
(2) (3) (4) (5) (6) (7)
Set point
LBA detec-
tion time
Area where LBA
is not detected LBA detection
time
LBA detection
time
LBA detection
time
LBA band LBA band
LBA band
LBA Level
LBA Level
PV
PV