DAQ Pad 6508 loses its configuration...anyone know of any possible reasons?

[REash]

Hello,

I'm using a NI DAQ Pad 6508 in a LabVIEW application.  I am using all ports as outputs to a relay card.  My 6508 device "locks up" at seemingly random times.  By "locking up", I mean that the 6508 loses it configuration (the green LED on it shuts off), and it is "locked" into the last output state prior to the "lockup".  This causes my relay card to freeze at that last state.  The 6508 will return to normal state after cycling power or unplugging and replugging in the USB cable.  Does anyone know of any possible reasons for why this could happen to the 6508?

Thanks!

Ryan

[REash]

Actually, I have two of these DAQPad 6508s in my system, and only one of them is doing this.  However, when I swap them around, the one that messes up is always the one that is connected to the 2nd of 2 relay card stacks that I am using.  Could something be wrong with the relay stack it is connected to that could cause the DAQPad to lose its configuration????  How would that be possible?  Or could it be something in software that could cause this??  Also, is there a way to reconfigure (allow the green LED to turn back on) the DAQPad without manually pulling the USB plug or cycling power?

[MickeyD]

Hi Ryan,

I was looking into your issue and it seems that you are having power failure problems.  How are the 6508s being powered, do you have external power sources, or is it powered by the USB port?  If you do not have external power supplies I would recommend we look to that as the option, because running two of them is probably trying to draw to much current from your USB bus. 

If you are using external power supplies, then it is possible that either your power supply is damaged, or the power supply connector to the DAQpad is damaged.  You could check your power supplies pretty simply by making sure that you can read the expected voltage off of them with a multimeter. 

This link describes a similar situation, were a power supply connector was damaged.

Problem of Power 2 DaqPAD 6508 boards

Please let me know if you have any further trouble with this issue.

Have a great day,

Michael D
Applications Engineer
National Instruments

[REash]

Michael,

I did see that thread when I was searching for an answer, but that does not seem to pertain to me.
As I stated in my previous post, I am using two of these devices, and the one that keeps losing connection to the PC is always the one connected to a certain bank of 4 relay cards on its outputs.  So it is NOT the same DAQPad that is failing all the time.
So I was wondering if there was a problem with one of the relay cards which could somehow cause the 6508 to lose connection with the PC (and how would that be possible?), or if my LabVIEW program has some problem in a section of code that uses those relay cards which could cause this problem (again, is that even possible?).  I am currently swapping the relay cards out one at a time to see if one of them is causing this.  The bad thing is that the problem is so random and can take hours to appear, so the process of going through each relay card is taking a while.  The only thing I can think of is that somehow one of the ICs on one of the relay cards is going bad, which sometimes draws a bunch of current from the 5V rail coming from the DAQPad (and the USB bus), thus causing the DAQPad to lose communication with that USB bus.

FYI, I am running the 6508s off of the supplied external power supplies, not the USB bus.

Any more thoughts, please let me know.

Thanks,
Ryan