DAQmx PCI 6251 cannot communicate...fixed but now shows random sine waves across all input channels

[boogata]

We had been getting an occasional error (201003) when running our custom LabView code, meaning it could not access the measurement device.  We run analog inputs from the BNC-2090A in voltage mode.  We were able to fix it by simply shutting down the computer and restarting.  Recently, however, the problem has not been fixing itself with a shut down sequence.  Upon opening the Measurement and Automation Explorer, we noticed a small "red X" next to the PCI-6251 DAQ device.  We deleted the old and created a new NI-DAQmx device, which seems to have fixed our communication problems with the A/D board and PCI device.  However, now when we run our custom LabView code, all we see are periodic sine waves with amplitude of 10V across all input channels? 

[gaving]

MAX (Measurement and Automation Explorer) does not allow for adding of "real" devices.  It appears that your PCI device is no longer showing up (thus the red "x").  MAX allows you to delete it (think of it as a way to tell MAX that you unplugged the device and you want MAX to forget about it).  When you created a new device, you created a "simulated" device, which will return simulated data (the sine wave across all channels).

You need to figure out why your pci device is not showing up in MAX.  I would look in Windows Device Manager and see if your PCI device is showing up there. (and under what heading)

[boogata]

That makes sense.  After several restarts, we noticed that the power light on the A/D board stopped lighting up.  We had been disconnecting the cables multiple times throughout the troubleshooting process but the light had always come back on with each shutdown/restart.  We decided to open the computer and reseat the PCI card into the motherboard, thinking that perhaps playing with the cables had exacerbated a loose connection somewhere. When we restarted, the original device was found in MAX, and we simply deleted our simulated device and everything is back to normal.  We suppose that random events like bumping the desk had caused the connection to work sometimes but not others.  Thanks for the help!