User`s guide

Section 1 — An Operator’s Quick Tour of Profit Optimizer Displays
1.2 Control Concepts You Need to Understand
4 Profit Optimizer User's Guide 1/00
Honeywell Inc.
MV Modes
There are two modes you can set to tell a controller how to use the output of an
MV: RMPC, OPR. Table 1-3 explains how the controller uses the output of an
MV for these modes.
Table 1-3 MV Modes
Mode Action on the MV
RMPC The variable is available for Profit Optimizer control.
OPR MV adopts the configured status: FFWD or SERV.
• FFWD = MV is treated as a feedforward disturbance.
• SERV = MV is dropped from both the prediction and control calculations.
AUTO For Profit, this standard TDC 3000 mode is not meaningful. MVs are treated as if they
were in OPR.
Critical Variables
Critical variables are variables the controller must use. Any CV, MV, DV, BDV or
CC can be set critical. The critical setting is a control flag that tells the controller
that the variable is a required value in its calculations. As a required value, the
variable must be used in the prediction and control calculations at every execution
interval.
If the variable is unavailable or bad, the controller shuts down and sheds control to
the default regulatory mode. Critical variables cannot be dropped or set OFF.
The number of controller executions that a bad or unavailable critical variable can
be tolerated before the controller relinquishes control can be set through an
associated operating parameter for CVs and BDVs.
Constraint
Handling
Occasionally, Profit Optimizer cannot immediately move one or more CVs within
range without sending other CVs out of range. When this condition exists,
COORDINATING displays on the Optimizer Bar as the optimizer's status (see
Table 1-8 for other optimizer statuses).
COORDINATING indicates that the optimizer is resolving intricate process
relationships, and that it may take several optimizer executions to correct the
disturbance.
Constraint conflicts are common in processes where variables are coupled or highly
parallel.