Table of Contents
Advertisement
F
Fieldbus
™
OUNDATION
December 2022
constant limit is set to indicate that the value is constant, and the OUT status is
Good.
The Uncertain - EU range violation status is always set, and the PV status is set
high or low limited if the sensor limits for conversion are exceeded.
In the STATUS_OPTS parameter, you can select from the following options to
control the status handling:
•
BAD if Limited: Sets the OUT status quality to Bad when the value is higher or
lower than the sensor limits.
•
Uncertain if Limited: Sets the OUT status quality to Uncertain when the value is
higher or lower than the sensor limits.
•
Uncertain if in Manual mode: The status of the output is set to Uncertain when
the mode is set to Manual.
Note
The transmitter must be in Manual or Out of Service mode to set the status
option.
Note
The AI block only supports the BAD if Limited option. Unsupported options are
not grayed out; they appear on the screen in the same manner as supported
options.
8.8.12
Advanced features
The AI function block provided with the Rosemount Fieldbus devices provides
added capability through the addition of the following parameters.
•
ALARM_TYPE: Allows one or more of the process alarm conditions detected by
the AI function block to be used in setting its OUT_D parameter.
•
OUT_D: 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 conditions.
•
VAR_SCAN: Time period in seconds over which the variability index
(VAR_INDEX) is computed.
•
VAR_INDEX: Process variability index measured as the integral of average
absolute error between PV and its mean value over the previous evaluation
period. this index is calculated as a percent of OUT span and is updated at the
end of the time period defined by VAR_SCAN.
158
Manual
00809-0500-4880
Emerson.com/Rosemount
Advertisement
Table of Contents
