Orthogonal Regions and Concurrency (Statechart Module)

LabVIEW 2010 Statechart Module Help

Edition Date: June 2013

Part Number: 372103F-01

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When a superstate contains two or more regions, those regions are called orthogonal regions. For example, in the following figure, Region 1 and Region 2 are orthogonal.

Substates in orthogonal regions are concurrent, which means that while the superstate is active, the statechart can be in exactly one substate from each orthogonal region during each statechart iteration. For example, in the previous figure, the statechart can be in State 3 and State 5 concurrently. Substates that exist within the same region, such as State 2 and State 3 in the previous figure, cannot be active concurrently.

Note  Some textbooks refer to orthogonal regions as AND-states.

Concurrency is different from parallelism. Concurrent substates take turns being active during each statechart iteration, whereas parallel substates are active simultaneously. The LabVIEW Statechart Module does not support parallel state activity.

The statechart enters orthogonal regions in descending alphabetical order of the region name. For example, in the previous figure, the statechart enters Region 1 before entering Region 2. Double-click the name of a region to change the name.

Tip  Try to avoid situations in which the actions of a substate depend on the results of a concurrent substate. This configuration might result in unexpected behavior or invalid data.

You can create one transition to and from multiple substates in orthogonal regions.

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