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Manual
00809-0500-4880
Figure 8-1: Function Block Internal Structure
A. Input events
B. Execution control
C. Output events
D. Input parameter linkages
E. Input snap
F. Processing algorithm
G. Output snap
H. Output parameter linkages
I. Status
Once the inputs are snapped, the alorithm operates on them, generating outputs
as it progresses. Algorithm executions are controlled through the setting of
contained parameters. Contained parameters are external to function blocks and
do not appear as normal input and output parameters. However, they may be
accessed and modified remotely, as specified by the function block.
Input events may affect the operation of the algorithm. An execution control
function regulates the receipt of input events and the generation of output events
during execution of the algorithm. Upon completion of the algorithm, the data
internal to the block is saved for use in the next execution, and the output data is
snapped, releasing it for use by other function blocks.
A block is a tagged logical processing unit. The tag is the name of the block.
System management services locate a block by its tag. Thus, the service personnel
need only know the tag of the block to access or change the appropriate block
parameters.
Function blocks are also capable of performing short-term data collection and
storage for reviewing their behavior.
Rosemount OCX8800A
F
Fieldbus
™
OUNDATION
December 2022
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