PXI-6509 and DAQmx buffer use/control?

[Bryan]

I've pretty much given up on triggered digital acquisition due to project time constraints and the fact that it's taking me so long to try to find information on it, so I'm just collecting several points of data, roughly 3-5 full square wave cycles and processing the data afterward.

The problem I'm running into though, is that occasionally, in my collected data, I get what appears to be a buffer reset in my data. I'll have a square wave that will have a little blip, or extremely wide "high" cycle amid normal "good" collected cycles.

What I think is happening is that the card is missing some of the signal when it resets the read point to the start of the buffer, so the little abnormalities are actually the end of one buffer width spliced to the beginning of the next.

Now, with DAQmx, and this card, I am not allowed any buffer control with digital acquisition. I can't even read what the current 'read point' in the buffer is, tell it where to start reading or anything. The only thing it appears I can control is the buffer size, but I'm not sure if it's even doing anything because when I do this, I see no difference in my acquired data.

Does anybody know any way to get around this problem, or should I continue to write little digital wave processing subVIs that will find and eliminate the odd-ball wave cycles?

Also, just FYI, I'm not concerned about the 'splice' for viewing purposes, I'm doing calculations with the collected data, and inconsistant cycles are affecting the outcome stability of the calculations.

Thanks guys!

[Bryan]

If nobody can answer that, can someone at least tell me if and how I can set the sampling rate on this PXI-6509?