Time critical Loop in FP2010 becomes indeterminate.

[cdreike]

I have a time critical while loop running on my field point. I also have another subvi that is at lowest priority that publishes 3 floats for the host PC to read. As soon as I enable the subvi, the time critical loop becomes indeterminate. Disabled, the main loop is OK. BTW it is a 20ms loop for a PID. There is about 3ms of sleep time. I could go up to 25ms.   I am using RT-FIFO to transfer data to the low priority subvi.

Why would the time critical loop be pre-empted by the low priority subvi?

Is there another more efficient way to send the data over to the host?

I am running LV6.1. Customer does not want to upgrade at this time.

Thanks,

Chris

[Khalid]

Hi Chris,

Is the "subVI" in question really a subVI of the higher-priority VI?  If yes, that would make it run at higher-priority as well -- probably not what you want to do. 

See this for further details:  http://digital.ni.com/public.nsf/allkb/D7E975105812F0C586256A6B005B4957

I would keep the two VIs separate (to keep their priorities separate) and transfer data via LV2-style globals between them.

-Khalid