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17. Appendix H
17.1. Important Functional Considerations
Function
Migrating to new
system software
release or moving a
device to another
Link.
Using Sequential
Control Module output
to push a NaN value
to a fieldbus device.
Fieldbus device
receives value with
status from a
Experion function
block.
Fieldbus device
receives value without
status from a
Experion function
block for use as float.
Fieldbus device
receives value without
status from a
Experion function
block for use as value
with status.
536
Experion PKS Series A Fieldbus Interface Module User's Guide
Indication
Device is active and its
block icons are green.
FIM will block write of NaN
value to fieldbus device
and SCM will indicate a
failure at that step.
If NaN value is delivered
to FIM for output, status
will be set to BAD and
value will be changed to
0.0 when sent to fieldbus
device.
No status byte
accompanies float data
type (such as is used by
limits, gains, tuning
parameters, etc.). FIM will
block write of NaN value to
fieldbus device. Last
successfully written value
will probably be retained
by the device.
If NaN value is delivered
to FIM for output, status
will be set to BAD and
value will be changed to
0.0 when sent to fieldbus
device.
Honeywell
Consideration
Before starting a software migration or
a device move, prepare a device by
putting its blocks in their Out-Of-
Service (OOS) mode in the following
order.
Function Block(s)
Transducer Block(s)
Resource Block
See the section
Preparing Fieldbus Device for a Move
or Software
Migration in this document
for more details.
Configure SCM so that it will not
attempt to push a NaN (Not-a-Number)
value as an output to a fieldbus device.
Be sure to understand the device's
reaction to receiving 0.0 value with
BAD status in configured situation.
If the device's behavior in the situation
is not acceptable, configure the
Experion logic to prevent it from
attempting to send NaN to the fieldbus
device.
Be sure to understand the device's
reaction to receiving 0.0 value with
BAD status in configured situation.
R400
July 2010
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