Specifications

2 Building Models
2-8
Signal Types
Inputs
The plant inputs are the independent variables affecting the plant. As shown in “MPC
Modeling” on page 2-2, there are three types:
Measured disturbances
The controller can't adjust them, but uses them for feedforward compensation.
Manipulated variables
The controller adjusts these in order to achieve its goals.
Unmeasured disturbances
These are independent inputs of which the controller has no direct knowledge, and for
which it must compensate.
Outputs
The plant outputs are the dependent variables (outcomes) you wish to control or monitor.
As shown in “MPC Modeling” on page 2-2, there are two types:
Measured outputs
The controller uses these to estimate unmeasured quantities and as feedback on the
success of its adjustments.
Unmeasured outputs
The controller estimates these based on available measurements and the plant model.
The controller can also hold unmeasured outputs at setpoints or within constraint
boundaries.
You must specify the input and output types when designing the controller. See “Input
and Output Types” on page 2-14 for more details.
More About
• “MPC Modeling” on page 2-2