Why does my hardware turn on when my vi is opened but not even run?

Question

I have tracked down the culprit vi to be Digital Group Config.vi in the \DAQ\zadvd.llb. Whenever I open Labview for the *first* time with any vi that contains this vi, my hardware (pumps, valves connected via PCI-DIO-96 and PCI-485/2) turn on. I don't even run the vi. (If I leave Labview open, close the initialisation vi and open it again, this does NOT happen.) My initialisation vi accesses this vi (digital group config), but things are turning on before I can even run the vi!?! How can I avoid this?
Many thanks - Steve

Answer 1

I can't say precisely, but I suspect it has to do with the way the low-level drivers are done. In LV with drivers that take the form of some type of external code (CIN, DLLs, etc) there is code that runs when you execute the VI calling it, and some code that executes when you load the driver into memory. Typically this load-time behavior is things like initializing memory, setting up memory structures it will use, and that sort of thing.
The long and the short of it is that you will have to design your hardware such that any operations that happen at startup don't have unintended and undesired effects.
Mike...
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