Ring Controls

Mutually exclusive items can include things like trigger modes. For example, use a ring control for users to select from continuous, single, and external triggering.

Access ring controls on the Controls » Style » Ring & Enum palette.

Ring controls appear as pull-down menus that users can cycle through to make selections.

You can use a ring control to select the cases of a Case Structure. The Case Structure uses the numeric value of ring items to select cases. The data type of a ring control is numeric.

In general, to work with ring controls, do the following:

1. Add the ring control to the front panel.
2. Edit the control to add selectable items to the control.

LabVIEW includes four types of ring controls:

Text ring—Users select among string items and can increment/decrement through entries.

Menu ring—Users select among string items in a control that resembles a dropdown menu.

Picture ring—Users select among images and can increment/decrement through entries.

Text & picture ring—Users select among image–string pairs and can increment/decrement through entries.

By default, LabVIEW assigns sequential values that correspond to the order of the items in the list. Ring items are zero-indexed, starting with the first item. However, when you configure the list of items for a ring control, you can also assign a specific numeric value to each item.

You can also configure the ring control so users can enter numeric values that are not already associated with any entries in the list of items defined for the control. To enter an undefined value in the ring control at run time, click the control, select <Other> from the shortcut menu, enter a numeric value in the digital display that appears, and press the Enter key. The undefined value appears in the ring control in angle brackets. LabVIEW does not add the undefined value to the ring control list.