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PID (PID » Series) (G Dataflow)

Version:
    Last Modified: March 31, 2017

    Implements a PID controller in the Series form.

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    feedforward input

    Value of the feedforward control.

    This input accepts an array of double-precision, floating-point numbers if setpoint is an array.

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    manual control

    Settings for the manual control mode.

    This input accepts an array of clusters if setpoint is an array.

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    manual

    A Boolean that specifies whether to use the manual control mode.

    True Uses the manual control mode.
    False Uses the automatic control mode.

    Default: False

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    manual input

    Value of the control output when you use the manual control mode.

    Default: 0

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    reset

    A Boolean that specifies whether to reset the internal parameters, such as the integrated error, of the controller.

    True Resets the internal parameters.
    False Does not reset the internal parameters.

    Set reset to True if your application must stop and restart the control loop without restarting the entire application.

    This input accepts an array of Booleans if setpoint is an array.

    Default: False

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    setpoint

    Setpoint value, or desired value, of the process variable.

    This input accepts a double-precision, floating-point number or an array of double-precision, floating-point numbers.

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    process variable

    Measured value of the process variable.

    This input accepts an array of double-precision, floating-point numbers if setpoint is an array.

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    PID gains

    Proportional gain, integral gain, derivative gain, and filter coefficient parameters of the controller.

    This input accepts a cluster or an array of clusters.

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    proportional

    Proportional gain of the controller.

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    integral

    Integral time constant of the controller, in seconds.

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    derivative

    Derivative time constant of the controller, in seconds.

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    filter coefficient [a]

    Derivative lowpass filter coefficient of the controller.

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    output range

    Range for the control output value.

    If the control output value is outside output range, this node coerces the value to fall within the range and returns the coerced value as the control output value. This node implements integrator anti-windup when the control output is saturated at the specified minimum or maximum value.

    This input accepts an array of clusters if setpoint is an array.

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    output high

    Maximum control output value.

    Default: Infinity

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    output low

    Minimum control output value.

    Default: -Infinity

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    dt

    Loop-cycle time, or interval in seconds, at which this node is called. dt must be greater than 0.

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    setpoint weighting

    Corrections to apply to the error values of the controller. setpoint weighting tunes the proportional action and the derivative action.

    This input accepts an array of clusters if setpoint is an array.

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    proportional weighting [beta]

    Relative emphasis of setpoint tracking to disturbance rejection.

    The valid value range is [0, 1]. Use the default value for most applications.

    Default: 1

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    derivative weighting [gamma]

    An amount by which to weight the error applied to the derivative action.

    The valid value range is [0, 1]. Use the default value to avoid the derivative kick.

    Default: 0

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    output

    Control output of the PID algorithm that is applied to the controlled process.

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    error

    Difference between the setpoint and the process variable.

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    actions

    Values of the proportional action, the integral action, and the derivative action in the PID algorithm.

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    proportional

    Value of the proportional action.

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    integral

    Value of the integral action.

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    derivative

    Value of the derivative action.

    Algorithm Definition

    The following transfer function represents a PID controller in the Series form:

    C s ( s ) = K c ( 1 + 1 T I s ) ( T D s + 1 α s T D s + 1 )

    where

    • K c is the proportional gain
    • T I is the integral time constant
    • T D is the derivative time constant
    • α s is the derivative filter coefficient

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: This product does not support FPGA devices


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