![background image](http://html1.mh-extra.com/html/brainchild/btc-9300/btc-9300_user-manual_2800920053.webp)
3 12 Loop Break Alarm
3 12 Loop Break Alarm
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
A1FN with LB.
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
as a loop break alarm.
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.
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
holding function even if it is set with holding or latching/holding mode. See
for the descriptions of these alarm modes.
Section 3-8
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
A1FN with LB.
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
as a loop break alarm.
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.
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
holding function even if it is set with holding or latching/holding mode. See
for the descriptions of these alarm modes.
Section 3-8
Loop Break Conditions are detected during a time interval of 2TI1 ( double of
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
decrease ) while the control variable MV1 has reached to its maximum ( or
minimum ) value within the detecting time interval, a loop break alarm ( if
configured ) will be actuated.
Loop Break Conditions are detected during a time interval of 2TI1 ( double of
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
decrease ) while the control variable MV1 has reached to its maximum ( or
minimum ) value within the detecting time interval, a loop break alarm ( if
configured ) will be actuated.
Process
Controller
Switching
Device
Switching
Device
Heater
Sensor
Figure 3.18
Loop Break Sources
Figure 3.18
Loop Break Sources
Loop Break Alarm ( if configured ) occurs when any following condition
happens:
1. Input sensor is disconnected ( or broken ).
2. Input sensor is shorted.
3. Input sensor is defective.
4. Input sensor is installed outside ( isolated from ) the process.
5. Controller fails ( A-D converter damaged ).
6. Heater ( or generally, chiller, valve, pump, motor etc. ) breaks or fails or
uninstalled.
7. Switching device ( used to drive heater ) is open or shorted.
Loop Break Alarm ( if configured ) occurs when any following condition
happens:
1. Input sensor is disconnected ( or broken ).
2. Input sensor is shorted.
3. Input sensor is defective.
4. Input sensor is installed outside ( isolated from ) the process.
5. Controller fails ( A-D converter damaged ).
6. Heater ( or generally, chiller, valve, pump, motor etc. ) breaks or fails or
uninstalled.
7. Switching device ( used to drive heater ) is open or shorted.
Loop Break Sources : Sensor, Controller, Heater, Switching Device
Loop Break Sources : Sensor, Controller, Heater, Switching Device
Loop Break Alarm 1
Loop Break Alarm 2
Setup : A1FN = LB
A1MD = NORM, LTCH
Setup : OUT2 = =AL2
A2FN = LB
A2MD = NORM, LTCH
Loop Break Alarm 1
Loop Break Alarm 2
Setup : A1FN = LB
A1MD = NORM, LTCH
Setup : OUT2 = =AL2
A2FN = LB
A2MD = NORM, LTCH
UM93001C
53