Why do boolean indicator outputs toggle when true is written repeatedly?

[Dave123]

Hi,

I'm using an LED boolean indicator in a sub vi connected to an output terminal.

If TRUE is repeatedly written to it then it toggles between ON and OFF as though it were a push button switch and each TRUE received was someone pushing the switch.

If I disconnect it from the output terminal then it behaves as expected, staying ON if TRUE is repeatedly received.

Why does it do this, how can I fix it?

Also, how can I turn all breakpoints off collectively without removing them?

Thanks,
Dave G
(LabView V7.0)

[johnsold]

Can you post an example which exhibits this behavior?

From your description it sounds as though something is re-initializing the indicator to default each time the VI is called, but that does not explain the terminal connection factor. Is it a control or indicator? Controls may switch to default when the subVI is called if nothing is wired to the terminal.

I rarely use breakpoints, so I cannot offer much expertise on that part of your question. The help file on breakpoints does not seem to offer anything except manual insertion and removal.

Lynn

[waldemar.hersacher]

Hi Dave,

go to File>>VI Porperties>>Execution and check if "Clear indiators if called" is checked.

If this is checked it clears the indicator when the VI is called. If you set the value to TRUE this value will be given back to the calling VI.

This behaviour was introduced to allow simpler programming. Think of a programm with various cases. There is only one case where you want to set the indicator to TRUE. If you haven't the above flag you need to set it to FALSE in all other cases. This forces to move the terminal outside of the case and to wire a lot of FALSE constants to the tunnel (nowadays we have the "use default if unwired" mechanism which makes the flag unnesseccary).

[Dave123]

Thanks, not sure why that should cause it to toggle TRUE/FALSE though?

I've managed to get round the problem by assigning FALSE to the indicator at the start of the VI before doing anything else.

Thanks.
Dave.