
F-CIM 77
DEVIATION/ALARM CALCULATION - 3
NOT REUSABLE
INPUTS NAME SYMBOL DATAPOINT
S
n-1
SETPOINT SP3 C209
A PROCESS VARIABLE PV3 C208
PARAMETERS SETPOINT SLEW RATE T13 C225
CONTROL ZONE C23 C222
ALARM INDEX AIX3 B350
ALARM LIMIT 1 PL13 C211
ALARM LIMIT 2 PL23 C212
ALARM DEADBAND ADB3 C213
OUTPUTS
S
n
DEVIATION DV3 C229
ALARM A PA13 L182
ALARM B PA23 L183
TRUE SETPOINT TSP3 C227
Description:
This module calculates and loads the deviation value based on setpoint (S
n
) and
process variable (A). Before the calculation is performed the setpoint value is con-
ditioned so as not to exceed the rate of change limit specified by T1. If the calcu-
lated deviation falls within the CZ value, then deviation is forced to 0.0. This
module also determines if alarm conditions exist based on AIX, PL1, PL2 and
ADB. Results of the alarm tests are loaded to PA1 and PA2. Refer to Section
4.1.6 of Instruction Bulletin 53MC5000 for an explanation of AIX values.
MODULAR CONTROLLER CUSTOMIZATION GUIDE
3-25
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