This function block provides a comprehensive PID controller with setpoint and actual value conditioning and a characteristic function.

		L_CT1P_ProcessController
LREAL	-	lrSetValue	lrOut	-	LREAL
BOOL	-	xLoadActvalue	lrOutRed	-	LREAL
LREAL	-	lrActValue	lrSetRampValueOut	-	LREAL
LREAL	-	lrDelayTime	lrDeviation	-	LREAL
LREAL	-	lrGain	xLimitActive	-	BOOL
LREAL	-	lrGainAdapt	xError	-	BOOL
LREAL	-	lrResetTime	eErrorID	-	L_IE1P_Error
LREAL	-	lrRateTime
BOOL	-	xReset
BOOL	-	xLoadIntValue
LREAL	-	lrIntValue
LREAL	-	lrAcc
LREAL	-	lrDec
LREAL	-	lrInfluence
LREAL	-	lrRedRange
LREAL	-	lrRedGain
LREAL	-	lrPosLimitValue
LREAL	-	lrNegLimitValue
ARRAY [...] OF LREAL	-	alrXValues
ARRAY [...] OF LREAL	-	alrYValues

Inputs

Name Data type	Information/possible settings
lrSetValue LREAL	Process setpoint
xLoadActvalue BOOL	Initialise ramp function generator and PT1 filter. In the Lenze setting, the ramp function generator is deactivated.
	TRUE	The actual value lrActValue is loaded to the ramp function generator and PT1 filter. The current system deviation is zero.
	FALSE	The ramp function generator runs from the actual value loaded via lrActValue to the setpoint pending at lrSetValue with the acceleration/deceleration set.
lrActValue LREAL	Actual process value
lrDelayTime LREAL	Filter time constant for the actual value Unit: s Initial value: 0.001 (with this value, the filter is not active.)
lrGain LREAL	Controller gain (P component) Initial value: 1.0000 The setting '0.0000' resets the PID controller.
lrGainAdapt LREAL	Value for adapting the controller gain The lrGainAdapt input value is evaluated via a parameterisable characteristic function first and is then adapted to the controller gain. In the characteristic default setting (y = 1), lrGainAdapt has no effect. The controller gain has a direct impact.
lrResetTime LREAL	Controller reset time (I component) Unit: s Initial value: 1.0000 The setting '0.0000 s' deactivates the I component.
lrRateTime LREAL	Controller rate time (D component) Unit: s Initial value: 0.000 (with this value, the D component is deactivated.)
xReset BOOL	Reset PID controller to zero.
	TRUE	PID controller is reset to zero.
	FALSE	PID controller is activated.
xLoadIntValue BOOL	TRUE	Load integrator: the I component of the PID controller is set to the value pending at the lrIntValue input.
lrIntValue LREAL	Scaled value to which the I component of the PID controller is set by setting xLoadIntValue to TRUE.
lrAcc LREAL	Acceleration for ramp generation Setting '0': maximum acceleration, i.e. the speed difference is generated within one cycle.
lrAcc LREAL
lrDec LREAL	Deceleration for ramp generation Setting '0': maximum deceleration, i.e. the speed difference is reduced within one cycle.
lrInfluence LREAL	Value for the evaluation of the lrOut output signal The evaluated lrOut output signal is displayed at lrOutRed . lrInfluence := 1 -> lrOut = lrOutRed
lrRedRange LREAL	Range of system deviation with reduced gain/sensitivity Initial value: 0.0
lrRedGain LREAL	Gain of the system deviation in the range of reduced sensitivity Initial value: 0.0
lrPosLimitValue LREAL	Positive output limit value for lrOut Initial value: 2147483647
lrNegLimitValue LREAL	Negative output limit value for lrOut Initial value: -2147483647
alrXValues ARRAY [1...5] OF LREAL	X values of the characteristic function Array positions 1 ... 5 correspond to interpolation point values X1 ... X5. Initial value: X1, X3, X4, X5 = 0.0 X2 = 1.0
alrYValues ARRAY [1...5] OF LREAL	Y values of the characteristic function Array positions 1 ... 5 correspond to interpolation point values Y1 ... Y5. Initial value: Y1, Y2 = 1.0 Y3, Y4, Y5 = 0.0

Outputs

Name Data type	Value/meaning
lrOut LREAL	Output signal Is limited internally to the lrPosLimitValue and lrNegLimitValue input values.
lrOutRed LREAL	Output signal evaluated via input signal lrInfluence
lrSetRampValueOut LREAL	Current setpoint of the ramp function generator
lrDeviation LREAL	System deviation
xLimitActive LREAL	TRUE	Limitation of the output signal is activated.
xError BOOL	TRUE	An error has occurred. For details see eErrorID .
eErrorID L_IE1P_Error	If xError = TRUE: Error number for the error that has occurred.

Extended functional description

Gain (P component)

The controller gain can be adapted via the lrGainAdapt input and a parameterisable characteristic function.

Reset time (I component)

By setting the xLoadIntValue input to TRUE, the I component of the controller is set to the value pending at the lrIntValue input.

Rate time (D component)

This turns the PID controller into a PI controller or, if the I component has also been deactivated, into a P controller.

Adaptation of the controller gain via characteristic function

The controller gain can be adapted via the lrGainAdapt input and a parameterisable characteristic function.

In the characteristic default setting (Y = 1.0), lrGainAdapt has no effect; the controller gain ( lrGain ) has a direct impact:

Only with the characteristic settings X1 = 0.0, Y1 = 0.0, X2 = 1.0, and Y2= 1.0, lrGainAdapt has a direct impact on the controller gain:

By changing the characteristic, the impact of lrGainAdapt on the controller gain can be evaluated in percent:

Selection of the characteristic

The characteristic can consist of up to five interpolation points which are defined by the arrays of alrXValues and alrYValues .

The same array numbers of alrXValues[n] and alrYValues[n] correspond to one pair of values/interpolation point (X _n , Y _n ).

The first pair of values ( alrXValues[1] and alrYValues[1] ) always applies.

The X values of the characteristic must be entered in ascending order (X1 < X2 < ... < X5).

If the ascending chain of X values is interrupted, this corresponds to the end of the characteristic (see the following examples).

Based on the pair of values that was valid last, extrapolation takes place on both sides.

Characteristic examples

	1	2	3	4	5
X	0 %	100 %	0 %	0 %	0 %
Y	100 %	100 %	0 %	0 %	0 %

	1	2	3	4	5
X	40 %	90 %	100 %	0 %	0 %
Y	40 %	140 %	115 %	0 %	0 %

System deviation within the reduced sensitivity

A reduced controller dynamics at low system deviations serves to have a positive effect on the damping behaviour of the control loop.

A tolerance zone within which the system deviation is transferred to the controller with a lower gain can be set via the lrRedRange input.

The percentage to which the gain is to be reduced within the tolerance zone specified is set in lrRedGain .

Controller influence

The lrInfluence input serves to evaluate the lrOut controller output in percent. The output signal evaluated is provided at lrOutRed .

Ramp function generator

The lrSetValue input setpoint can be led via a ramp function generator with linear ramps to prevent setpoint step-changes at the input.

The positive and negative acceleration for the ramp generation are set in lrAcc and lrDec .

By setting the xLoadActValue input to TRUE, the ramp function generator is initialised with the value pending at the lrActValue input. This produces a zero system deviation.

Low pass in actual value path

The actual value lrActValue that is loaded by setting xLoadActValue to TRUE can be controlled via a PT1 filter.

L_CT1P_ProcessController