Reference Manual
00809-0100-4021, Rev FB
August 2011
4-19
Rosemount 3144P
F
OUN
DATION
F
ie
ldb
us
Alarm Priority
Alarms are grouped into five levels of priority:
Status
When a PV is passed from one function block to another, it passes a STATUS
along with the PV. The STATUS can be: GOOD, BAD, or UNCERTAIN. When
a fault occurs in the device, the PV will look at the last value with a STATUS of
GOOD and the STATUS will change from GOOD to BAD, or from GOOD to
UNCERTAIN. It is important that the control strategy that uses the PV also
monitors the STATUS to take appropriate action when the STATUS changes
from GOOD to either BAD or UNCERTAIN.
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 determines 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
Set the output status to
Bad
if the sensor is violating a high or low limit.
Uncertain if Man Mode
Set the output status of the Analog Input block to
uncertain
if the actual
mode of the block is Man.
NOTE
The instrument must be in Out of Service mode to set the status option.
Advanced Features
The following parameters provide the capabilities to drive a discrete output
alarm in the event that a process alarm (HI_HI_LIM, HI_LIM, LO_LO_LIM,
LO_LIM) has been exceeded.
ALARM_TYPE
ALARM_TYPE allows one or more of the process alarm conditions
(HI_HI_LIM, HI_LIM, LO_LO_LIM, LO_LIM) detected by the AI function block
to be used in setting its OUT_D parameter.
OUT_D
OUT_D is the discrete output of the AI function block based on the detection
of process alarm condition(s). This parameter may be linked to other function
blocks that require a discrete input based on the detected alarm condition.
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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