Ignore certain values when graphing

Question

Hi all,
I am currently using labview to automatically QC check data from a weather station. I have one VI that checks the incomming data for errors and outputs the data with any corrections to a text file. I have another VI that opens the text file and graphs the results. If the first VI finds a obvious error, it exchanges the bad data point with -9999 to make sure the error is obvious. Therefore, a series of temperature data may start like this: 45,45.4,800,46.5,47.3 and end up like this 45,45.4,-9999,46.5,47.3
My question is this. Is there anyway to have labview ignore certain values when graphing. I need the auto ranging feature turned on to insure that the graphs are legible, but if the -9999 value is included it creates a problem when the scales try to incorporate it. I need to be able to set labview to graph everything but to ignore the -9999 value when determining the scale. This would create an auto-ranged graph with the -9999 value simply going off the graph.
Tim

Answer 1

You can replace the -9999 values in your array data with the double precision value NaN (Not a Number - you can actually type that into a numeric control). LabVIEW will leave an empty spot when graphing, and it won't upset your autoscaling.
Jarrod S.
National Instruments