Hi winterfresh -
The graph is only updated each time that particular case is called, which is when the Timeout event occurs. The timeout event is called when the front panel hasn't generated an interrupt or registered event within a particular timeout period. This period is defined by the number wired to the hour glass on the top left fo the event structure. Currently it is the value you originally used, which 10,000 ms, or 10 seconds.
The most obvious approach to resolve the issue would be to reduce that number right down. If you don't have anything you need to handle in other cases or event then you can make the timeout to be quite quick - say, 100ms. You'll just need to play around a little here.
I don't know the full extent of your code but you do have the option in moving your stepper-motor and peak detection code into the timeout event - thus removing the need to have a separate case to 'get value'. If this is a main part of the program and is something you need to happen every timeout period then it isn't a bad idea.
