Things have been hectic lately, so I outsourced today's nugget. This one comes from one of my colleagues in LabVIEW R&D,
Aristos Queue:
One issue that comes up when using custom probes is that they only run their block diagrams when the value updates, i.e. when a value flows through the wire being probed. There are two cases that are thus difficult to handle in the custom probe:
- Configuration of the probe: You cannot have controls that interact with each other to set up complex configuration settings. For example, if you have written a complex custom probe, you might have a checkbox option on the probe. But you cannot have that checkbox enable/disable other controls on the custom probe since it is not actually running any time other than when the value updates.
- Exploration of data: Once the value of the probe does update, the only exploration of the data that you can do is whatever is available when indicators are not running. For example, you might get a waveform into a chart. You could have radio buttons that apply different filters to the waveform so you can look at different aspects of it, but changing those radio buttons after the data updates won't change the filter applied to the data.
In both of these cases, you can use XControls. If you put an XControl on the front panel of a custom probe, the XControl will run its code whenever the user triggers one of the XControls events -- clicking, mouse moving, etc. This lets you put active behavior into an otherwise passive custom probe.
-D
P.S. - Check out past nuggets
here.
