ControlP (FB)¶

FUNCTION_BLOCK ControlP

Short Description¶

Proportional controller (P-controller)

The direction of action (inverted/direct) is also adjustable.

Typical application: Controlled systems with actuators where storage is possible.

Portrayal¶

Interfaces¶

Inputs¶

Name
Datatype

Range

Init-Value

Function

rX REAL
Analog actual value

rW REAL
Analog setpoint

xEn BOOL
Enable the Controller

Outputs¶

Name
Datatype

Range

Init-Value

Function

rY REAL 0.0
Output signal of the controller

rDiff REAL
Control deviation

xLimitActive BOOL
Status - Exceeding the limit value

Setpoints / Parameters¶

Name
Datatype

Range

Init-Value

Function

rMax REAL 100.0
Upper absolute limit value of the output signal

rMin REAL -100.0
Lower absolute limit value of the output signal

rKp REAL 0.0 ... 2.0
Gain factor

rOffset REAL 0.0
Offset

rYDisabled REAL 0.0
Switch-off value

eAction eControlMode eControlMode.Inverted
Direction of action of the controller (inverted, direct)

eManModeN eManNum eManNum.Auto
Operating mode for the controller output signal

rManValue REAL
Output signal in manual mode

Functional Description¶

General¶

This function block contains a proportional-acting controller (P-controller).
The output signal of the controller rY is calculated as follows when the controller is enabled (xEn = TRUE) and in the controller automatic mode (eManModeN = eManNum.Auto):

rY = rKp * (( actual value + offset ) - ( setpoint value ))

Depending on the direction of action of the eAction controller, the actual and setpoint values ​​are determined as follows:

eAction
Actual value

Setpoint value

Formula

Function

eControlMode.Invertiert rW rX rY = rKp * (( rW + rOffset ) - ( rX ))
Direction of action - Inverted

eControlMode.Direct rX rW rY = rKp * (( rX + rOffset ) - ( rW ))
Direction of action - direct

Enabling input xEn¶

If the enabling input is not active (xEn = FALSE), the switch-off value rYDisabled is transferred to the output rY
(Requirement: eManModeN = eManNum.Auto) and limited by the absolute limits.

When the enable input is active (xEn = TRUE), the output signal is calculated according to the formula above and transmitted to the output rY
(Requirement: eManModeN = eManNum.Auto) and limited by the absolute limits.

Control deviation rDiff¶

The control deviation is calculated according to the following formula and transmitted to the output rDiff.

rDiff = actual value - setpoint value

Absolute rMin and rMax limits¶

The output signal of the controller rY is limited by the absolute limit values ​rMin downwards and rMax upwards.
The absolute limit rMin is set to the current value of rMax - 0.1 if it is > = the current value of rMax.
Excluded is only the manual operation mode for the output signal of the controller (eManModeN = eManNum.Man).

Status - limit exceeded xLimitActive¶

The status of the limit violation is activated (xLimitActive = TRUE), if there is a limit violation.
The status of the limit violation is not activated (xLimitActive = TRUE), if there is a limit violation.

A limit value violation occurs if the output signal of the controller rY reaches/exceeds the upper limit value rMax or
reaches/falls below the lower limit rMin.

Operating mode for the output signal of the eManModeN controller¶

The parameter eManModeN allows for the output signal rY to be switched from automatic to manual mode and vice versa.
In manual mode, the output signal rY adopts the output signal in manual mode rManValue.
The setpoint / parameter rManValue is overwritten with the current value of the output signal rY with each transition to automatic mode.

eManModeN rY
Function

eManNum.Auto
Signal according to the formula / switch-off value

Automatic operation - Output signal

eManNum.Man rManValue
Manual operation - Output signal

Visualization¶

Information¶

Element
Authors

Date
Version
Notes

Function
Adam Bartod 02.2017 1.0
Initial version

Programming
Adam Bartod 02.2017 1.0
Initial version

Test Jochen Reu 11.2017 1.0
Initial version

Documentation
Jochen Reu 11.2017 1.0
Initial version

Codesys¶

InOut:

Scope	Name	Type	Initial	Comment
Input	rX	REAL		Analog actual value
	rW	REAL		Analog setpoint
	xEn	BOOL		Enable the Controller
	rYMax	REAL	100	Upper absolute limit value of the output signal
	rYMin	REAL	-100	Lower absolute limit value of the output signal
	rKp	REAL	2	Gain factor
	rOffset	REAL	0	Offset
	rYDisabled	REAL	0	Switch-off value
	eAction	eControlMode	eControlMode.Inverted	Direction of action of the controller (inverted, direct)
	eManModeN	eManNum	eManNum.Auto	Operating mode for the controller output signal
	rManValue	REAL		Output signal in manual mode
Output	rY	REAL	0	Output signal of the controller
	rDiff	REAL		Control deviation
	xLimitAktiv	BOOL		Status - Exceeding the limit value