XY graph: write an error

[Cary]

Hello,
I wish to write a character like an "x" or a null character (like a empity
space) when my VI generate a read error.

How can I do?

Thanks

[altenbach]

If I understand you correctly, you show data in an xy-graph. If an error occurs you want to switch to either (1) a different point style or (2) generate a gap in the graph.

For case (1), switch to a second plot while generating NaN on plot 1 (and vice versa). For case 2, simply add points where x or y is NaN during the error condition.

I have attached a simple interactive example (LabVIEW 7.0). Run it and press the button to simulate the error condition. Let me know if this is what you want.