17. Appendix H 
17.1. Important Functional Considerations 
536  Experion PKS Series A Fieldbus Interface Module User's Guide   R400 
 Honeywell July 2010 
Function Indication  Consideration 
Migrating to new 
system software 
release or moving a 
device to another 
Link.  
Device is active and its 
block icons are green.  
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.  
Using Sequential 
Control Module output 
to push a NaN value 
to a fieldbus device.  
FIM will block write of NaN 
value to fieldbus device 
and SCM will indicate a 
failure at that step. 
Configure SCM so that it will not 
attempt to push a NaN (Not-a-Number) 
value as an output to a fieldbus device.  
Fieldbus device 
receives value with 
status from a 
Experion function 
block.  
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. 
Be sure to understand the device's 
reaction to receiving 0.0 value with 
BAD status in configured situation.  
Fieldbus device 
receives value without 
status from a 
Experion function 
block for use as float. 
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 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. 
Fieldbus device 
receives value without 
status from a 
Experion function 
block for use as value 
with status. 
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. 
Be sure to understand the device's 
reaction to receiving 0.0 value with 
BAD status in configured situation.