NI DAQ 6501 DOESNT RESPOND

[wb2nvy]

Please see attached vi. When running this subvi in my main program, the DAQ outputs don't respond to the DAQ Assistant task inputs. If I run MAX and do the test panel, the DAQ responds properly, and subsequent runs of this vi work ok. It acts like the DAQ doesn't want to wake up until it's stimulated by MAX first. I use this DAQ often in other programs and never had this problem. Anybody know what I'm doing wrong?

[EricS.]

Hi wb2nvy,

Have you tried running a DAQ Assistant in a VI by itself?  Just do a simple DO task in a new VI to see if the card is working in a DAQ Assistant.

If that works, run through your main program either with highlight execution enabled, or stepping through and poling the data input to the DAQ Assistant to verify it is getting the correct values on the first run.  If the DAQ Assistant is getting incorrect data to output, then the outputs will not work as expected. 

Message Edited by Eric S on 04-21-2010 01:52 PM

[wb2nvy]

Yes Eric, I made a vi with just the DAQ task and it behaved the same way. And I stepped through it in highlight mode and inputs were correct.

In my main vi, I have another DAQ Assistant addressing other outputs on the same DAQ, and it works ok. I now combined all outputs into the same DAQ Assistant and the problem has gone away. The problem seems to have been related to having 2 DAQ Assistants talking to the same DAQ but with tasks for different outputs. Thanks for your help.