SI Transfer Function Estimation Express VI
Owning Palette: Parametric Model Estimation VIs
Installed With: System Identification Toolkit
Estimates a discrete or continuous transfer function model for a SISO unknown system. For discrete models, this VI supports the direct, indirect, and joint input-output identification methods.
| Dialog Box Options |
| Block Diagram Inputs |
| Block Diagram Outputs |
 Place on the block diagram |
Find on the Functions palette |
Dialog Box Options
| Parameter | Description |
|---|---|
| Signals | Displays the signals used to estimate the system, including the stimulus signal, reference signal, response signal, and estimated response signal. |
| Data type | Specifies the data type for the input signal(s). Contains the following options:
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| Model type | Specifies the type of model to estimate. Contains the following options:
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| Numerator order | Specifies the order of the numerator of the system model. |
| Denominator order | Specifies the order of the denominator of the system model. |
| Estimation method | Specifies the estimation method to use for discrete systems. Contains the following options:
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| Controller numerator | Specifies the numerator coefficients of the discrete, linear controller. |
| Controller denominator | Specifies the denominator coefficients of the discrete, linear controller. |
| Controller structure | Specifies the controller position in the feedback loop. If the controller is set before the plant, select Feedforward-path. If the controller is set after the output, select Feedback-path. |
| Zero-Pole cancellation tolerance | Determines zero-pole cancellations. If the difference between the location of a pole and a zero is within the tolerance, this VI removes the zero-pole pair. |
| System diagram | Displays the system diagram of the closed-loop system. |
| Estimated model | Displays the mathematical equation and sampling rate of the estimated transfer function model. |
Block Diagram Inputs
| Parameter | Description |
|---|---|
| stimulus signal | Specifies the input waveform or array of a stimulus signal. |
| reference signal | Specifies the input waveform or array of a reference signal. |
| response signal | Specifies the input waveform or array of a response signal. |
| sampling rate | Specifies the sampling frequency in hertz. For discrete models, sampling rate is the system sampling rate. For continuous models, sampling rate is used to convert the continuous model to a discrete model before simulating the output. |
| error in (no error) | Describes error conditions that occur before this VI or function runs. |
Block Diagram Outputs
| Parameter | Description | ||
|---|---|---|---|
| system model out | system model out returns information about the model structure, nominal or estimated parameters, identification result, and so on. Use the Model Management VIs to retrieve the information system model out contains.
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| coefficients | Returns the coefficients of the transfer function (TF) model. Contains the following elements:
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| continuous delay | Returns the estimated delay of the continuous system in seconds. | ||
| error out | Contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. |
This Express VI operates similarly to the following VIs and functions: