Structures (PDA Module, Touch Panel Module)
Owning Palette: Programming VIs and Functions
Use the structures to build VIs.
There are some caveats to using structures in PDA or Touch Panel VIs.
| Palette Object | Description |
|---|---|
| Case Structure | Has one or more subdiagrams, or cases, exactly one of which executes when the structure executes. The value wired to the selector terminal determines which case to execute and can be Boolean, string, integer, or enumerated type. Right-click the structure border to add or delete cases. Use the Labeling tool to enter value(s) in the case selector label and configure the value(s) handled by each case. |
| Conditional Disable Structure | Has one or more subdiagrams, exactly one of which LabVIEW uses for the duration of execution, depending on the configuration of the conditions of the subdiagram. Use this structure when you want to disable specific sections of code on the block diagram based on some user-defined condition. Right-click the structure border to add or delete a subdiagram. |
| Event Structure | Has one or more subdiagrams, or event cases, exactly one of which executes when the structure executes. The Event structure waits until an event happens, then executes the appropriate case to handle that event. Right-click the structure border to add new event cases and configure which events to handle. Wire a value to the Timeout terminal at the top left of the Event structure to specify the number of milliseconds the Event structure should wait for an event to occur. The default is –1, indicating never to time out. |
| Flat Sequence Structure | Consists of one or more subdiagrams, or frames, that execute sequentially. Use the Flat Sequence structure to ensure that a subdiagram executes before or after another subdiagram. |
| For Loop | Executes its subdiagram n times, where n is the value wired to the count (N) terminal. The iteration (i) terminal provides the current loop iteration count, which ranges from 0 to n-1. |
| Formula Node | Evaluates mathematical formulas and expressions similar to C on the block diagram. The following built-in functions are allowed in formulas: abs, acos, acosh, asin, asinh, atan, atan2, atanh, ceil, cos, cosh, cot, csc, exp, expm1, floor, getexp, getman, int, intrz, ln, lnp1, log, log2, max, min, mod, pow, rand, rem, sec, sign, sin, sinc, sinh, sizeOfDim, sqrt, tan, tanh. There are some differences between the parser in the Mathematics VIs and the Formula Node. |
| Global Variable | Use global variables to access and pass data among several VIs. |
| Inline C Node | Adds C code or assembly code to the block diagram. |
| Local Variable | Use local variables to read or write to one of the controls or indicators on the front panel of a VI. |
| Shared Variable | Represents a shared variable on the block diagram. To bind a Shared Variable node to a shared variable from the active project, place a Shared Variable node on the block diagram and double-click it or right-click it and select Select Variable from the shortcut menu to display the Select Variable dialog box. You also can drag a shared variable from the Project Explorer window onto the block diagram of a VI in the same project to create a Shared Variable node. |
| Stacked Sequence Structure | Consists of one or more subdiagrams, or frames, that execute sequentially. Right-click the structure border to add and delete frames or to create sequence locals to pass data between frames. Use the Stacked Sequence structure to ensure a subdiagram executes before or after another subdiagram. |
| While Loop | Repeats the subdiagram inside it until the conditional terminal, an input terminal, receives a particular Boolean value. The Boolean value depends on the continuation behavior of the While Loop. Right-click the conditional terminal and select Stop if True or Continue if True from the shortcut menu. You also can wire an error cluster to the conditional terminal, right-click the terminal, and select Stop on Error or Continue while Error from the shortcut menu. The While Loop always executes at least once. |