Creating LabVIEW Projects with the Real-Time Project Wizard (RT Module)
Use the Real-Time Project Wizard to create a new project that defines RT targets and includes VIs and other application files. You can create projects with the Real-Time Project Wizard using one of three architectures—continuous communication, state machine, or custom.
Continuous Communication Architecture
Use a continuous communication architecture to create data acquisition applications that can log data to disk and continuously communicate with a host computer to provide a user interface.
With the continuous communication architecture, you can select an application configuration that uses one or two Timed Loops in the RT target VI.
- One loop—The RT target VI uses a Timed Loop to control the timing and execution of the application tasks.
- Two loops—The RT target VI uses two Timed Loops running at different priorities to control the timing and execution of the application tasks. The higher priority Timed Loop controls the deterministic tasks. The lower priority Timed Loop controls user interface communication and file I/O tasks.
You can provide a user interface for the real-time application using a VI running on the host computer or using a LabVIEW remote front panel to connect to the RT target VI.
- Host VI—Uses LabVIEW shared variables to send user interface data out of the RT target VI. A VI that runs on the host computer accesses the user interface data and displays the data on a front panel.
- Remote Panel—Uses a LabVIEW remote front panel to view the front panel controls and indicators of the RT target VI. You cannot use remote front panels with a single Timed Loop configuration if the application requires determinism. The Real-Time Project Wizard creates an HTML file that you can publish using the Web Server of the RT target. You can use this HTML file to access the front panel of an RT target VI from the host computer.
State Machine Architecture
Use a state machine architecture to implement complex decision-making algorithms represented by state diagrams or flow charts. The state machine architecture can implement any algorithm described by a Moore machine. For each state in a state diagram, a Moore machine performs a specific action that runs for a finite amount of time. To prevent data loss, the time to execute each action must be short enough to keep all acquired data in memory on the target. The RT target also must be able to send all the data back to the host computer in one package. The state machine architecture separates communication and non-deterministic tasks from deterministic tasks and executes them before and after deterministic tasks.
The Real-Time Project Wizard generates an RT target VI that uses a Case structure to define the states of the state diagram. The Real-Time Project Wizard also generates a VI that runs on the host computer to provide a user interface, which you can use to select the state to execute on the RT target. The host VI uses shared variables to trigger the execution of a particular state on the RT target. The RT target VI executes the subdiagram for the state you select and returns the results to the host VI.
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Note You can use the LabVIEW Statechart Module to design and implement state-based applications on a real-time target. Refer to the National Instruments Web site for information about the Statechart Module. |
Custom Project
Use a custom project architecture to add a blank VI or import existing VIs to run on the host computer or RT target.