How to use the Zoom for Pocket PC 2003?

[yqin]

I try to use the LabVIEW7.1 PDA module zoom feature in my Pocket PC 2003. But I can not make it works right. For example, if I try to zoom to rectangle, the graph does not draw in the selected rectangle.

I attached my code.

[Caroline Bright]

Hello,

I have taken a look at your vi and believe I understand your problem. The vi works if you allow the sine wave to draw to completion and then zoom in on a certain part of the graph. You cannot zoom while the graph is still drawing because the Zoom button click is not registered. Your program is looping inside the case structure for the run button so it does not see that the zoom button is pressed.
Also, I see that when you click Zoom and then draw the sine wave, the wave is not drawn inside the selected area. The graph goes back to its default values. This behavior is because the x and y max and min are set inside the graph properties. Whether this is set by autoscaling or by setting the max and min in the graph properties page, these values overwrite the zoom rectangle values. In LabVIEW for the PC you can set max and min values programmatically through property nodes. However, property nodes are currently not supported in LabVIEW for PDA. So, unfortunately there is no current way to programmatically change the values so that the sine wave is drawn inside the selected zoom region.

Thanks,
Caroline
National Instruments

[yqin]

I modified the code after I read your repy. But problem still there.

See the attached code.

[Caroline Bright]

Hello,

Unfortunately, even with the modified code the same problem exists. This is a limitation of LabVIEW for PDA. Each time the waveform is drawn it will either autoscale the graph or go back to the max and min values you set in the properties box. The only way to override this behavior in LabVIEW is to use property nodes. However, property nodes are not available in LabVIEW PDA just in LabVIEW for PC. So, there is no current way to have the sine wave draw inside the zoom box you specify.

Sorry,
Caroline
National Instruments