Loop Break Alarm - Brainchild BTC-2500 User Manual

3 13 Loop Break Alarm

3 13 Loop Break Alarm
A1FN selects LB if alarm 1 is required to act as a loop break alarm. Similarly, if A1FN selects LB if alarm 1 is required to act as a loop break alarm. Similarly, if
alarm 2 is required to act as a loop break alarm, then set OUT2 with=AL2 and alarm 2 is required to act as a loop break alarm, then set OUT2 with=AL2 and
A1FN with LB. A1FN with LB.
TIME, A1SP , A1DV and A1HY are hidden if alarm 1 is configured as a loop break TIME, A1SP , A1DV and A1HY are hidden if alarm 1 is configured as a loop break
alarm. Similarly, TIME, A2SP , A2DV and A2HY are hidden if alarm 2 is configured alarm. Similarly, TIME, A2SP , A2DV and A2HY are hidden if alarm 2 is configured
as a loop break alarm. as a loop break alarm.
One of 4 kinds of alarm modes can be selected for alarm 1 and alarm 2. These One of 4 kinds of alarm modes can be selected for alarm 1 and alarm 2. These
are : Normal alarm, Latching alarm, Holding alarm and Latching/Holding alarm. are : Normal alarm, Latching alarm, Holding alarm and Latching/Holding alarm.
However, the Holding mode and Latching/Holding mode are not recommended However, the Holding mode and Latching/Holding mode are not recommended
to be chosen for loop break alarm since loop break alarm will not perform to be chosen for loop break alarm since loop break alarm will not perform
holding function even if it is set with holding or latching/holding mode. See holding function even if it is set with holding or latching/holding mode. See
Section 3-9 Section 3-9 for the descriptions of these alarm modes. for the descriptions of these alarm modes.
Loop Break Conditions are detected during a time interval of 2TI1 ( double of Loop Break Conditions are detected during a time interval of 2TI1 ( double of
integral time, but 120 seconds maximum ). Hence the loop break alarm integral time, but 120 seconds maximum ). Hence the loop break alarm
doesn't respond quickly as it occurs. If the process value doesn't increase ( or doesn't respond quickly as it occurs. If the process value doesn't increase ( or
decrease ) while the control variable MV1 has reached to its maximum ( or decrease ) while the control variable MV1 has reached to its maximum ( or
minimum ) value within the detecting time interval, a loop break alarm ( if minimum ) value within the detecting time interval, a loop break alarm ( if
configured ) will be actuated. configured ) will be actuated.
Switching Switching
Device Device
Loop Break Sources : Sensor, Controller, Heater, Switching Device Loop Break Sources : Sensor, Controller, Heater, Switching Device
Loop Break Alarm ( if configured ) occurs when any following condition Loop Break Alarm ( if configured ) occurs when any following condition
happens: happens:
1. Input sensor is disconnected ( or broken ). 1. Input sensor is disconnected ( or broken ).
2. Input sensor is shorted. 2. Input sensor is shorted.
3. Input sensor is defective. 3. Input sensor is defective.
4. Input sensor is installed outside ( isolated from ) the process. 4. Input sensor is installed outside ( isolated from ) the process.
5. Controller fails ( A-D converter damaged ). 5. Controller fails ( A-D converter damaged ).
6. Heater ( or generally, chiller, valve, pump, motor etc. ) breaks or fails or 6. Heater ( or generally, chiller, valve, pump, motor etc. ) breaks or fails or
uninstalled. uninstalled.
7. Switching device ( used to drive heater ) is open or shorted. 7. Switching device ( used to drive heater ) is open or shorted.
Heater
Process Process
Controller
Sensor
UM25001C
Loop Break Alarm 1 Loop Break Alarm 1
Setup : A1FN = LB Setup : A1FN = LB
A1MD = NORM, LTCH A1MD = NORM, LTCH
Loop Break Alarm 2 Loop Break Alarm 2
Setup : OUT2 = =AL2 Setup : OUT2 = =AL2
A2FN = LB A2FN = LB
A2MD = NORM, LTCH A2MD = NORM, LTCH
Figure 3.18 Figure 3.18
Loop Break Sources Loop Break Sources
53