Use the ring constant to create a list of strings you can cycle through, similar to a ring control on the front panel.
Set the value by clicking the constant with the Operating tool. Set the string with the Labeling tool and enter the string. To add another item, right-click the constant and select Add Item Before or Add Item After from the shortcut menu. Select a string from the ring constant before you run a VI, because you cannot change the selection while a VI is running.
The ring constant associates each string with an unsigned 16-bit integer. If you display a value from a ring constant the number displays instead of the string associated with it. If you need a set of strings that do not change, use this constant. Although you can change the representation of a ring constant to any numeric type except complex, the value is always an integer from zero to n-1, where n is the number of strings in the ring constant.
You cannot change the value of the ring constant while the VI runs. You can assign a label to this constant.