.IndustrialControlSystems.Controllers.Digital.PID_2dof_TDO_FullyEventBased

Information

Description

Proportional + Integral + Derivative with two degree of freedom controller with Automatic, Tracking, Manual mode and bias signal. The controller is implemented in its incremental form algorithm.
The control law is defined as

            [                      1                        sTd                      ]
  CS(s) = Kp[ (bSP(s) - PV(s)) + ----- (SP(s) - PV(S)) + -----------(cSP(s) - PV(s)) ]
            [                     sTi                     1 + sTd/N                  ]

Name	Description	Conditional?
SP	Set Point	NO
PV	Process Variable	NO
CS	Control Signal	NO
satHI	CS at HIGH saturation	NO
satLOW	CS at LOW saturation	NO
TR	Track Reference signal	YES (useTS)
TS	Track Switch signal	YES (useTS)
Bias	Biasing signal	YES (useBIAS)
MAN	Manual Switch signal	YES (useMAN)
CSinc	Control Signal increment	YES (useMAN)
Finc	Forbid increment	YES (useForbid)
Fdec	Forbid decrement	YES (useForbid)

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

Time Division Output (TDO)

The Control Signal CS computed by the PID controller can have two values: CSmin and CSmax.
The result is a rectangular wave, which duty cycle is proportional to the control action computed by the controller.
The sampling time Ts is NOT divided in sub intervals. The sampling time is divided in two parts, depensing on the value of the control action.
In the first part the Control Signal is at the CSmax value, while CSmin in the remaining one.
With such an approach very high frequency sampling is avoided.

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 is true, 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.

Manual mode

If the boolean flag useMAN is true, the inputs MAN and CSinc are enabled.
When enabled, if the MAN signal is true the output CS can be manually controlled via the signals CSinc and CSdec, that respectively increment or decrement the control signal.

Forbid mode

If the boolean flag useForbid is true, the inputs Finc and Fdec are enabled.
When enabled, if the Finc signal is true the output CS cannot grow up, while if Fdec is true it cannot decrease.

Discretisation

The controller is implemented directly through an algorithm, that represents the discretised version of the continuous time controller.

Revisions

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