.IndustrialControlSystems.Controllers.Interfaces.Controller

Information

Description

Partial interface for a continuous/discrete time controller.
The model has the following ports

Name Description Conditional?

SP Set Point NO

PV Process Variable NO

CS Control Signal NO

TR Track Reference signal YES (useTS)

TS Track Switch signal YES (useTS)

Bias Biasing signal YES (useBIAS)

ATreq AutoTuning request YES (useAT)

And some of them can be conditionally selected, by specifying a boolean flag.

Name	Description	Conditional?
SP	Set Point	NO
PV	Process Variable	NO
CS	Control Signal	NO
TR	Track Reference signal	YES (useTS)
TS	Track Switch signal	YES (useTS)
Bias	Biasing signal	YES (useBIAS)
ATreq	AutoTuning request	YES (useAT)

AntiWindUp mode

If the boolean flag AntiWindup is tue the output of the block ( CS ) saturates at the values specified by CSmin and CSmax.

Tracking mode

If the boolean flag useTS, the inputs TS and TR are enabled.
When enabled, if the TS signal is true the output CS is forced to follow the track reference signal TR.

Discretisation

For each controller is defined a sampling time Ts and a coefficient alpha.
The discretisation of the continuos time transfer function has been performed with the bilinear transformation formula

                 z - 1 
  s = ------------------------------
        z*alpha*Ts - (alpha - 1)*Ts

that is equivalent to

Forward Euler (FE) if
```
alpha = 0
```
Backward Euler (BE) if
```
alpha = 1
```
Tustin (TU) if
```
alpha = 0.5
```

Revisions

Industrial Control Systems (v 1.0.0) : April-May 2012