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Figure 40 Functional schematic for Analog Output function block.
Description
Function Notes
Equation Options
R400
Experion PKS Series A Fieldbus Interface Module User's Guide
July 2010
The Analog Output function block converts the set point
(SP) value to a number that can be used by the hardware
associated with the CHANNEL selection. A functional
schematic of the block is shown in the previous illustration
for reference.
Can use either the Set point (SP) value after limiting
or the Process Variable (PV) value for the
BKCAL_OUT value.
Supports Out of Service (OOS), Local Override (LO),
Manual (Man), Automatic (Auto), Cascade (Cas), and
Remote Cascade (RCas) modes.
The conversion of Set point (SP) to percent of span is
based on the PV_SCALE range.
The conversion of the percent of span to a compatible
value for the hardware is based on the XD_SCALE
range.
Use the Increase to Close Option in IO_OPTS to
invert the span.
Use the Cascade mode to transfer the output of
another block to the Set point of the AO block.
If the hardware, such as a valve positioner, supports a
readback value, run this value backwards through the
XD scaling to act as the PV for this block. If this is not
supported, READBACK is generated from OUT.
In the Man mode, an operator can write a value to
OUT. A manufacturer must put operational limits in the
Transducer, where an operator cannot access them, to
permit the Man mode. If Man mode is not permitted, it
must be supported as a transition mode for exiting the
OOS mode
The SIMULATE parameter is for testing purposes only
and always initializes in the disabled state.
Temp = (SP - EU@0%) / (EU@100% - EU@0%)
[PV_SCALE]
Honeywell
10. Appendix A
10.2. Standard Function Blocks
389
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