Digital I/O

cancel
Showing results for 
Search instead for 
Did you mean: 

C application using USB 6009 only works if NI Max is open

Hello,

When running a simple C application using a USB 6009 device, a pulse is sent out on two digital lines, every 20 ms. The pulse length is 1 ms. The pulse is created by toggling the line high, waiting for a 1ms, and then setting it low.

The application works fine on a development computer using the latest NI drivers.

 

When running on another computer, using the same NI drivers, the application misses sending out about 20% of the pulses, and their length are no longer 1 ms, but more like 5 ms.

 

However, which is intriguing, if one opens the NI Max application, while running the C application, the pulse outputs becomes correct and behaves as on the development computer. 

 

Any ideas what can be causing this erratic behavior?

 

Best,

-Totte Karlsson

0 Kudos
Message 1 of 1
(1,371 Views)