Ignore multiple 'value change' events from a control

Each and every incremental movement of a numeric slider, dial, tank or thermometer control or continuously holding down the increment/decrement buttons on ordinary numeric controls, rings or enums will generate a series of value-change events that are queued up and subsequently acted on by an event structure that has been configured to watch for value-change events associated with the control.

If you were to grab and move a slider (after having noted its starting value) back and forth for several seconds before returning it to the starting value and releasing it, you will have generated several hundred value-change events of all the intermediate values that the slider has passed through.

This behavior is fine if you want to have the real-time position/value of the slider reported out.

In some cases however all you want to see is the final new value of the slider. An example of this is when the slider is being used to set some parameter of an instrument controlled by the VI and the parameter change is communicated to the instrument by way of a long command string and a slow serial communication link. In this case you most certainly do not want to wait while the intermediate values of the slider are also communicated to the instrument, you just want the final value sent.

Until the event structure is upgraded (which it most definitely needs to be!) so that it can be configured to distinguish between "report all value changes" and "report final value change" a workaround is needed.

This example shows one way of accomplishing that workaround.

Requirements

Filename: finalize_slider_events.llb

Software Requirements

Application Software: LabVIEW Full Development System 7.0
Language(s): LabVIEW

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