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Manual
00809-0500-4880
Figure 8-4: AI Function Block
OUT = The block output value and status
OUT_D = Discrete output that signals a selected alarm condition
The analog input (AI) function block processes field device measurements and
makes them available to other function blocks. The output value from the AI block
is in engineering units and contains a status indicating the quality of the
measurement. The measuring device may have several measurements or derived
values available in different channels. Use the channel number to define the
variable AI block processes.
The AI block supports alarming, signal scaling, signal filtering, signal status
calculation, mode control, and simulation. In Automatic mode, the block's output
parameter (OUT) reflects the process variable (PV) value and status. In Manual
mode, you can set OUT manually. The Manual mode is reflected on the output
status. A discrete output (OUT_D) is provided to indicate whether a selected alarm
condition is active. Alarm detection is based on the OUT value and user specified
alarm limits.
descriptions, and index numbers.
Table 8-19: Definitions of AI Function Block System Parameters
Parameter
ACK_OPTION
ALARM_HYS
Rosemount OCX8800A
Table 8-19
lists the AI block parameters and their units of measure,
Index number
23
24
Units
None
Percent
F
Fieldbus
™
OUNDATION
December 2022
Description
Used to set auto
acknowledgement of
alarms.
The amount the alarm
value must return within
the alarm limit before the
associated active alarm
condition clears.
147
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