LabVIEW
Indicator Refresh from Global Variable
Hi mem07,
I'd be inclined to use the FP string as the storage device (instead of a global), and let other parts of the program read it when they need to. The Value of the string is one of the string's Properties accessible via its reference. The reference could be put in a global, and shared that way, but this is a great application for a little "Driver" for the FP control - see attached. Initialize the driver once (passing it the FP string's reference) and after that just use the "driver" to manipulate the string. To get an object's reference, right-click on the object and choose create reference - wire this to initialize! 
Cheers!
Message Edited by tbd on 10-03-2007 03:36 AM
Hi mem07,
Some good answers have come up... Tbd is right - there is probably no reason to use a global. The string indicator will work just fine in storing your value. You mentioned that "there is only one indicator icon that I can access." By that statement, I assume you mean that there's only one terminal that lets you access the value in your front panel indicator or control.
A way around this that was mentioned by tbd is to use a reference and a property node. Yes, you could right click the control or terminal and select create->reference, wire it to a property node (Application Control Palette), and select the "value" property. Property nodes by reference are one of the slowest ways to update controls, though. This is also a pretty advanced technique for someone new to LabVIEW (good learning experience, though).
A slightly faster method is to right click your terminal and create->property node, selecting the value property. This property node is "implicit" because it doesn't use a reference.
The quick and dirty way to access the terminal's value is to create a local variable. Locals are frowned upon by the gurus almost as much as a global because they duplicate the value of the control in memory for each local - it'll get the job done, though, and they're refreshed faster than both property node types. To make a local variable, right click the control or terminal and select "Create->Local Variable". If you know about globals, you probably already know about locals.
Whew - that was a lot to type. The bottom line is that, every time you update the front panel control or indicator by any of these methods, it's functionally equivalant to using the terminal ("indicator icon.") The trouble is when you have multiple parts of your code updating the indicator at the same time, leading to a race condition. We'll leave that for another post.
I hope my rambling was helpful...
Jim
Some good answers have come up... Tbd is right - there is probably no reason to use a global. The string indicator will work just fine in storing your value. You mentioned that "there is only one indicator icon that I can access." By that statement, I assume you mean that there's only one terminal that lets you access the value in your front panel indicator or control.
A way around this that was mentioned by tbd is to use a reference and a property node. Yes, you could right click the control or terminal and select create->reference, wire it to a property node (Application Control Palette), and select the "value" property. Property nodes by reference are one of the slowest ways to update controls, though. This is also a pretty advanced technique for someone new to LabVIEW (good learning experience, though).
A slightly faster method is to right click your terminal and create->property node, selecting the value property. This property node is "implicit" because it doesn't use a reference.
The quick and dirty way to access the terminal's value is to create a local variable. Locals are frowned upon by the gurus almost as much as a global because they duplicate the value of the control in memory for each local - it'll get the job done, though, and they're refreshed faster than both property node types. To make a local variable, right click the control or terminal and select "Create->Local Variable". If you know about globals, you probably already know about locals.
Whew - that was a lot to type. The bottom line is that, every time you update the front panel control or indicator by any of these methods, it's functionally equivalant to using the terminal ("indicator icon.") The trouble is when you have multiple parts of your code updating the indicator at the same time, leading to a race condition. We'll leave that for another post.
I hope my rambling was helpful...
Jim
