Digital IO PCIe 6535 stops working

Question

I just had a mysterious problem with 10MHz Digital IO card PCIe 6535.
Some background:
I typically use it for generating simple waveforms like: (X,0,...,0,Y,0,0,0,...) ; where X is a sum of two bits (e.g. bit 6 + bit 0 = 64 + 1 = 65), and Y is a single bit or zero. Sometimes, I keep it generating waveforms overnight.
Problem:
It omits some of the bits. For example, when I tell it to pulse (66,0,0,0,...) , it gives me (64,0,0,0,...); if I say (4,0,...), it gives me (0,0,...). Looks like it does an "X AND 65" before accepting the command (well, I pulse (65,0,0,0,..) most frequently). So, I quit the executable (compiled from a VI), and check the VI for software bugs. It couldn't find any, so I run the VI, it worked! Then, I run the exe again, it worked fine! So, in essense, what I did was restarting the exe.
Currently, it is working, but I would like to know what caused this (I suspect the card is already aging?) and whether I can avoid it in the future. Any ideas?

Answer 1

Hi Raymond,
Any chance you could post your VI?  That behavior doesn't make sense, and isn't something that can happen due to aging of the product.
Also, what version of DAQmx are you using?
Thanks,
Keith Shapiro
National Instruments R&D