How can I implement upper/lower limits for a complex time-domain waveform using WaveformGraph ?

[Jeff Franks]

This use case is for testing how a part is put together on an assembly line. A particular variable is recorded and used as a model. This becomes the complex waveform that represents an ideal measurement. How can I use WaveformGraph to implement an upper and lower limit window, and flag the assembly if it goes outside the limits? Can I use the WaveformGraph as a UI component that is used by the operator to set and edit the upper and lower limits relative to the measured variable?

--jlf

[Torba]

Jeff,

Probably the most presentable way to accomplish this task would be to use XYcursors on the graph as limit lines.  You can hide the veritcal lines generated from the XYcursors by setting the VerticalCrosshairLength property to 0. You can then obtain the current Y axis position of the limit line by way of the YPosition property, and then compare this limit value to the data points that are coming in.  This approach would allow the user to be able to set the limits of the test by dragging the limit lines on the graph itself.

Another idea would be to have upper and lower limit numerical controls on the side of the graph.  The user would type the limit values in, and the application would continually make comparisons between the limits and the data points, and set a boolean to true if the point falls outside the range.

Regards,

Mike Torba
National Instruments