You are here: NI Home > Support > Product Reference > Manuals > LabVIEW FPGA Module 8.2 Help

Use the structures to control data flow.

If you use a global variable in an FPGA VI, the global variable maps directly to a register on the FPGA target. Use global variables to transfer data between loops efficiently.

Note  This palette is specific to FPGA targets and contains a subset of the VIs and functions that are on this palette when you edit a Windows or RT target VI.

Click the icons for function descriptions.

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.
Diagram Disable Structure	Has one or more subdiagrams, or cases, of which only the Enabled subdiagram executes. Use the Diagram Disable structure to disable a section of the block diagram.
Feedback Node	In For Loops and While Loops, transfers values from one loop iteration to the next.
Flat Sequence Structure	Consists of one or more subdiagrams, or frames, that execute sequentially. Right-click the structure border to add and delete frames. Use the Flat Sequence structure to ensure a subdiagram executes before or after another subdiagram. Data flow for the Flat Sequence structure differs from data flow for other structures. Frames in a Flat Sequence structure execute from left to right and when all data values wired to a frame are available. The data leave each frame as the frame finishes executing.
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.
Global Variable	Use global variables to access and pass data among several VIs.
Local Variable	Use local variables to read or write to one of the controls or indicators on the front panel of a VI.
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. The iteration (i) terminal provides the current loop iteration count, which is zero for the first iteration.

Subpalette	Description
Decorations	Use the decorations located on the Decorations palette to group or separate objects on a block diagram with boxes, lines, or arrows. These objects are for decoration only and do not modify data.
Timed Structures	Use the Timed Loop structure to control the rate at which a subdiagram executes.