Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller FLEXIBLE CONTROL STRATEGIES - Manual (Page 28)

2.7.14 DEVIATION/ALARM CALCULATION 0
The Deviation/Alarm Calculation 0 (D/C 0) 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 0 module follows the tables.
Inputs
WIRELIST SYMBOL DATA
TYPE
ASSIGNED VALUE
B152 PV0 C
B153 SP0 C
Output Datapoints: C119, C121, L110, L111
Parameters Parameters
SYMBOL DATAPOINT ASSIGNED VALUE SYMBOL DATAPOINT ASSIGNED VALUE
T1-0 C117 PL2-0 C104
CZ0 C114 ADB0 C105
PL1-0 C103 AIX0 B335
ADB0...alarm dead band
AIX0...control alarm mode
CZ0...control zone
DV0...deviation
PA1-0...alarm A active
PA2-0...alarm B active
PL1-0...alarm limit 1
PL2-0...alarm limit 2
PV0...process variable
SP0...setpoint
T1-0...setpoint slew rate
TSP0...control setpoint
Section 2. FCS Modules
DAC-0
2-21