17
Reference Manual
00809-0100-4772, Rev FA
Configuration and Operation
March 2016
Configuration and Operation
2.8.3 Process alarms
Process Alarm detection is based on the OUT value. Configure the alarm limits of the
following standard alarms:
High (HI_LIM)
High high (HI_HI_LIM)
Low (LO_LIM)
Low low (LO_LO_LIM)
In order to avoid alarm chattering when the variable is oscillating around the alarm limit, an
alarm hysteresis in percent of the PV span can be set using the ALARM_HYS parameter. The
priority of each alarm is set in the following parameters:
HI_PRI
HI_HI_PRI
LO_PRI
LO_LO_PRI
2.8.4 Alarm priority
Alarms are grouped into five levels of priority:
2.8.5 Status options
Status options (STATUS_OPTS) supported by the AI block are shown below:
Propagate fault forward
If the status from the sensor is Bad, Device failure or Bad, Sensor failure, propagate it to OUT
without generating an alarm. The use of these sub-status in OUT is determined by this
option. Through this option, the user may determine whether alarming (sending of an alert)
will be done by the block or propagated downstream for alarming.
Uncertain if limited
Set the output status of the Analog Input block to uncertain if the measured or calculated
value is limited.
BAD if limited
Set the output status to Bad if the sensor is violating a high or low limit.
Priority
number
Priority description
0 The alarm condition is not used.
1 An alarm condition with a priority of 1 is recognized by the system, but is
not reported to the operator.
2 An alarm condition with a priority of 2 is reported to the operator.
3-7 Alarm conditions of priority 3 to 7 are advisory alarms of increasing
priority.
8-15 Alarm conditions of priority 8 to 15 are critical alarms of increasing
priority.
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