Extending System Identification Assistant Projects with LabVIEW
In this help file, you learned how to complete the following procedures:
- Launch the LabVIEW System Identification Assistant in the LabVIEW SignalExpress environment
- Load signals and rebuild missing data
- Split data to use for model estimation and validation
- Normalize data for ease of calculation
- Estimate parameters of a system model
- View model information in the SignalExpress environment
- Compute the pole-zero plot for a model
- Validate the accuracy of a model
- Compare system models through model validation
- Save models to file
Converting to Block Diagrams
Without prior knowledge about programming in LabVIEW, you can use the System Identification Assistant to develop a model that reflects the behavior of a certain dynamic system. The LabVIEW System Identification Toolkit also provides LabVIEW VIs that you can use to preprocess raw data from a dynamic system and develop a model that reflects the behavior of that system.
You can use LabVIEW to convert System Identification Assistant projects to LabVIEW block diagrams to continue developing an application. You first can use the interactive tools in the System Identification Assistant to analyze and estimate models. You then can convert the sequence into a LabVIEW block diagram to build automated test programs.
The System Identification Assistant converts projects into block diagrams using the VIs that ship with the System Identification Toolkit. The System Identification steps in the Add Step menu do not convert into Express VIs.
Unlike creating a project with the System Identification Assistant, creating a LabVIEW application using the System Identification VIs requires basic knowledge about programming in LabVIEW. Refer to the LabVIEW Fundamentals manual and the Getting Started with LabVIEW manual for more information about the LabVIEW programming environment. In LabVIEW, access these manuals by clicking the corresponding links in the Getting Started window. Refer to the LabVIEW Help for more information about LabVIEW VIs and functions. In LabVIEW, access this help file by selecting Help»Search the LabVIEW Help.
Sweeping
The Sweep step repeatedly performs measurements with different parameter values. The System Identification Assistant converts the Sweep step into a For Loop in a LabVIEW block diagram. The System Identification steps in the Add Step menu can exist within a sweep, but they do not provide parameters that you can use within a sweep.
Using User-Defined Steps
You can build a user-defined VI to use in a Run LabVIEW VI step. The Run LabVIEW VI step runs a VI in the LabVIEW SignalExpress environment. When you import a LabVIEW VI, the System Identification Assistant maps the inputs of the VI as parameters and the outputs of the VI as outputs by default.
Further Examples
The System Identification Assistant provides several other example projects that demonstrate more capabilities of the System Identification Assistant. These projects are located in the National Instruments\Express Workbench\System Identification Assistant\Examples directory. You can modify an example project to fit an application, or you can copy and paste from one or more examples into a project that you create.
You can find the solution, Sample Project Solution.seproj, to the exercises in this help file, as well as an example of the ARMAX model you created, Sample ARMAX Model Solution.sim, in the National Instruments\Express Workbench\System Identification Assistant\Examples\getting_started directory.
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