Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller FLEXIBLE CONTROL STRATEGIES - Manual (Page 43)

2.7.25 DEVIATION/ALARM CALCULATION 1
The Deviation/Alarm Calculation 1 (D/C 1) module calculates and loads a Deviation Value (DV),
based upon the Setpoint (SP) and the Process Variable (PV). Before the calculation is performed,
the setpoint value is conditioned not to exceed the T1 rate of change limit. If the calculated devia-
tion falls within the Control Zone (CZ) value, the deviation is forced to 0.0. This module also deter-
mines if alarm conditions exist based on the Control Alarm Mode (AIX), both alarm limits (PL1 and
PL2), and the Alarm Deadband (ADB). Results of the alarm tests are loaded into active alarms 1
and 2 (PA1 and PA2). The tables that follow list the input variables and the parameters (e.g., T1,
AIX, etc.). An illustration of the Deviation/Alarm Calculation 1 module follows the tables.
Inputs
WIRELIST SYMBOL DATA
TYPE
ASSIGNED VALUE
B191 PV1 C
B192 SP1 C
Output Datapoints: C155, C157, L134, L135
Parameters Parameters
SYMBOL DATAPOINT ASSIGNED VALUE SYMBOL DATAPOINT ASSIGNED VALUE
T1-1 C153 PL2-1 C140
CZ1 C150 ADB1 C141
PL1-1 C139 AIX1 B340
ADB1...alarm dead band
AIX1...control alarm mode
CZ1...control zone
DV1...deviation
PA1-1...alarm A active
PA2-1...alarm B active
PL1-1...alarm limit 1
PL2-1...alarm limit 2
PV1...process variable
SP1...setpoint
T1-1...setpoint slew rate
TSP1...control setpoint
FCS 53MC5000 Flexible Control Strategies
2-36
DAC-1