Hi SETj!
I posted a similar question....
The answer is: there's not a fixed update rate that can be
granted, because NI 6509 update values "as fast as possible", this
means that it depends on system architecture (motherboard / processor
speed, thread priority...). Moreover, you cannot rely on "sample
clock", which doesn't exist on this board.
Of course, the fastest sample rate you can obtain is with
"vectorial" read/write, that is you define a task in which you
generate/read a fixed number of samples (say 1000). With this
technique, I sampled/generated bits spaced of 5 microseconds, while
with perform "scalar" read/write functions, I reached about 25
microseconds spacing. Of course, these values depends on the
features I mentioned abve.
An example of scalar read:
DAQmxReadDigitalU8( , ..., <samples per channel = 1> , ...);
DAQmxReadDigitalU8( , ..., <samples per channel = 1> , ...);
DAQmxReadDigitalU8( , ..., <samples per channel = 1> , ...);
etc...
An example of vectorial read:
DAQmxReadDigitalU8( , ..., <samples per channel = 1000> , ...);
Hope it helps, let me know!
graziano