I am using the USB-6501 to interface to a SemiLab laser Type tester. One digital output port turns power on to the laser thru a relay and three digital inputs return the status of the test station. All four signals are defined in the project as Global channels set to digital lines. The code reads a status at Port 1/bit 0 and then sets the power on at Port 1/bit 3. When the digital power control is set to 1, the DAQmx driver returns the NI Platform Services Error -50150, the software has entered and unknown state. With execution highlighting the problem is the same.
All IO operate correctly from Max using the test panel and from the project using the individual DAQ Assistant pages.
The system is running LV2010 Professional and DAQmx 9.4.0f1
The problem disappeared when I moved the power control line to port 2.0. Seems that the DAQmx software could not handle ins and outs on the same port over the USB.