6 Parameter Settings and Functions
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6.4.7 Loop Break Alarm [PAR4 → AL-1/AL-2 → LBA]
Diagnoses the control loop by monitoring the control subject's temperature changes
and sends out alarms if necessary.
Heating control: When control output MV is 100% or high limit (H-MV) and PV is not
increased over than LBA detection band (
LBA.B)during LBA monitoring time (LBA.T),
or when control output MV is 0% or low limit (
L-MV) and PV is not decreased below
than LBA detection band (
LBA.B) during LBA monitoring time (LBA.T), alarm output
turns ON.
Cooling control: When control output MV is 0% or low limit (L-MV) and PV is not
increased over than LBA detection band (
LBA.B) during LBA monitoring time (LBA.T),
or when control output MV is 100% or high limit (
H-MV) and PV is not decreased
below than LBA detection band (
LBA.B) during LBA monitoring time (LBA.T), alarm
output turns ON.
Common Causes of LBA Output On
Sensor Error (disconnection, short)
External Controller Error (magnet, auxiliary relay, etc.)
External Load Error (heater, cooler, etc.)
Misconnections and disconnections of external network.
Set alarm output mode(
) as loop break alarm (
) and you
can use loop break alarm.
LBA operates only when control output MV is low limit (
), 0%,
high limit (
), or 100%.
In case of AT (auto-tuning)/manual control/stop control, loop break
alarm (
) does not operates
When alarm reset is input, it initializes LBA monitoring start time.
6.4.7.1 LBA Monitoring Time [PAR4 → LBA.T]
You can set the LBA monitoring time to check changes in the control subject's
temperature.
Automatically setting with auto-tunning.
Setting
Group
Parameter Setting Range
Factory
Default
Unit
to
Sec