I am relatively new to LabVIEW and GPIB and am running into some difficulties with what looks to be an inconsistent VI due to timing issues.
The problem seems to be related to either the VISA read or VISA write VIs. I noticed the option to make the VISA VIs sync. or async., but am not completely sure what this means. I am under the impression that sync. would be synchronized with the processor's clock while async. is not. This, however, would make me believe async. would be used for applications where a VISA I/O operation must take less than one clock cycle. This seems impossible to me since there are numerous GPIB functions to be executed from a single VISA I/O VI.
When I use async. I/O operations, I get tim
eouts showing in NI Spy when waiting for an IO completion event.
I have looked in many references provided by NI but cannot find specific information on the difference between these two functions. Can anyone help me? Anything would be appreciated.
Also, some other small questions contributing to my confusion. Again, any help is appreciated.
Why is the timeout in viWaitOnEvent() set to 0 (or am I mistaken)?
Why do the viEnableEvent() always return VI_SUCCESS_EN indicating the specified event is already enabled?
Thanks for the time,
Chris
PS. If you are interested in helping me and are unclear to some of the details, please post any questions and I will provide any extra info.
