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Create Gain (PD » Academic) (G Dataflow)

Last Modified: December 18, 2017

Returns PD gains of a PD controller in the Academic form.

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derivative unit

Unit associated with the derivative gain.

This input accepts a ring or an array of rings.

Name Value Description
Hz 0 Specifies that the derivative gain is expressed in Hz.
s 1 Specifies that the derivative gain is expressed in seconds.
min 2 Specifies that the derivative gain is expressed in minutes.

Default: The default value of this input changes depending on the data type you wire. If you wire a ring to this input, the default is s. If you wire an array of rings to this input, the default is Hz.

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proportional unit

Unit associated with the proportional gain.

The relationship between the available units is K = 100/PB.

This input accepts a ring or an array of rings.

Name Value Description
Gain (K) 0 Specifies that the proportional gain is expressed in terms of proportional gain (K).
Band (PB) 1 Specifies that the proportional gain is expressed in terms of proportional band (PB).

Default: Gain (K)

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proportional

Value of the proportional component of the controller.

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

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derivative

Value of the derivative component of the controller.

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

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filter coefficient [a]

Derivative lowpass filter coefficient of the controller.

If you specify a value for filter coefficient unit, you must also specify a value for filter coefficient [a]. When filter coefficient unit is Alpha, the valid value range of filter coefficient [a] is [0, 1]. When filter coefficient unit is N, the valid value range of filter coefficient [a] is [1, 1000].

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

Default: NaN.

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filter coefficient unit

Unit of the derivative lowpass filter coefficients.

The relationship between the available units are as follows: N = 1/Alpha; Time Constant = 1/(2 * Pi * Cutoff Frequency).

This input accepts a ring or an array of rings.

Name Value Description
Alpha 0 Specifies that the filter coefficients are expressed in Alpha.
N 1 Specifies that the filter coefficients are expressed in N.
Cutoff Frequency 2 Specifies that the filter coefficients are expressed in Hz.
Time Constant 3 Specifies that the filter coefficients are expressed in seconds.

Default: Alpha

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action

Action of the controller.

This input accepts a ring or an array of rings.

Name Value Description
Reverse 0 The controller is reverse-acting.
Direct 1 The controller is direct-acting.

Default: Reverse

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PD gains

Proportional gain and derivative gain parameters of the controller.

This output can return a cluster or an array of clusters.

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proportional

Proportional gain of the controller.

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derivative

Derivative gain of the controller.

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filter coefficient [a]

Derivative lowpass filter coefficient of the controller.

Algorithm Definition

The following transfer function represents a PD controller in the Academic form:

C i ( s ) = K c ( 1 + T d s α i T d s + 1 )

where Kc is the proportional gain, Td is the derivative time constant, and α i is the derivative filter coefficient.

Where This Node Can Run:

Desktop OS: Windows

FPGA: This product does not support FPGA devices

Web Server: Not supported in VIs that run in a web application


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