USB-6281 no LEDS lit

[telsenbroich]

We are using a USB-6281 OEM NI board in our application.  We are using 24VDC to power to board.  The 24V comes from a power supply within our test system.  We have found that we loose communcation with the baord at seemingly random times.  Neither of the LEDs (amber or green) are lit when this happens.  The only way to regain communication is to cycle the power on our entire system.  I have tried just restarting the computer that is connected to the board via USB, and just restarted the software (Labwindows CVI 8.5, Test Stand 4.01) - neither helps.  I cannot communicate with the booard using MAX either.  The board shows up in MAX, but I get an error when I try to run a test panel and MAX locks up when I try to reset the board.  We are running NI-DAQmx 8.7.2.

We are using the connector that is recommneded to connect the 24Vdc to the board.  We have seen this issue on two different boards.  Currently, we have a Fer-rite EMI supporssor on the 24V line going into the board.  We have tried a shorted USB cable (~3 foot) as well.

Any suggestions are welcome.

Thank you in advance.

[Dustin_D]

telsenbroich,

Have you seen this issue across multiple computers or just on a single one?  Also any error given to you by MAX would be helpful to know.

Regards, 

[telsenbroich]

We have seen this on two computers. Both comptuers are running the same software and have the same type of NI board connected (USB-6281 OEM).  Unfortunately, I have not been able to obtain an error message from MAX as it usually locks up and we are having difficulty reproducing the problem.  I will try again to get an error number the next time this problem occurs.

[Dustin_D]

telsenbroich,

Check to see if this setting in your Device Manager is set under the USB Root Hub Properties.  Each instance will have this setting and you will want to make sure the box is unchecked.  I hope this helps!

 

Regards, 

[telsenbroich]

Thank you for the suggestion.  We found that when we expereinced this problem, we were also removing our USB drives incorrectly(we did not use the safe removal utility).  This either caused an error to occur or the board to completely shutdown.  Since we have been more careful removing our USB drives, we haven't had the problem occur as frequently.  I also followed you advice by turning OFF the "Allow this device to be shutdown" option.

Thank you for the help.