Emerson Rosemount 3144P Reference Manual page 180

F Fieldbus Configuration
OUNDATION
December 2019
4.10.5 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.
4.10.6 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.
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Reference Manual
00809-0100-4021
Rosemount 3144P