the digital relationship of scanRate and sampleRate

[not have]

Hello:
I'm using PCI-6024E DAQ board and labwindowscvi 5.0.1 to do some work.I failed to calculate the digital relationship of "sampleRate and scanRate" --- two parameters in the function "scan_op" of multichannels sample.Because when I set channelsnumber to 2(sample two AI channels),the scanRate to 500 scans per second and sampleRate to 800(400 samples per channel per second),I find sampling failed.When I change sampleRate to 1000(500 samples per channel per second) or 2000(1000 samples per channel per second),then sampling successed.So I think scanRate,sampleRate and channelsnumber must satisfy an digital relationship.But I failed to find it.If you know,please tell me,thanks.

[Filipe A.]

Hello;

A value of 0 for the Scan Rate means there is no delay between scans and the effective scanRate is sampleRate / numChans.

When scanRate is not 0, scanRate must allow a minimum delay between the last channel of the scan and the first channel of the next scan. This delay must be at least 11 ?s on the AT-MIO-16X and 6 ?s on the AT-MIO-16F-5 and AT-MIO-64F-5. For E Series devices, this delay corresponds to the speed of the board. For example, 1 ?s for an E-1 board, 2 ?s for an E-2 board, and so on.
Hope this helps.
Filipe
Applications Engineer
National Instruments