Honeywell Series A - Fieldbus Analog Input data manipulation

3. Fieldbus Integration With Experion System
3.2. Control Integration
R400 Experion PKS Series A Fieldbus Interface Module User's Guide 45
July 2010 Honeywell
CM
CPM/CEE
FIM
Fieldbus
Device
FIM
Analog
Input
Transducer
PID
AOC
OUT
PV
OP
OP
AOC = Analog Output Channel
CEE = Control Execution Environment
FIM = Fieldbus Interface Module
OP = Output
PID = Proportional, Integral, Derivative
CM = Control Module
CPM = Control Processor Module
PV = Process Variable
Figure 6 Integration of fieldbus device analog input signal with Control
Builder control strategy
Fieldbus Analog Input data manipulation
Whe
n the OUT from the fieldbus analog input function block is wired to the PV input for
a PID function block, the Control Builder creates a CEE input agent to handle the analog
input from the fieldbus block. The block-like input agent maps the data structure (DS-65)
of the OUT parameter to the Control Builder PV with status parameter. It interprets the
value portion in fieldbus terms and converts it to Control Builder representation. The
floating-point representation is identical, in most cases, but the fieldbus +/-infinity value
must be converted to a Control Builder representation.
If the fieldbus status byte indicates "BAD", the value must be converted to Not a Number
(NaN) for Control Builder representation. The fieldbus data quality of good, bad, and