usb 6361%2C Sampling rate for 8 channel

[Dide_]

What is the maximum rate for simultaneously reading from 8 channels on USB 6361 card?

I've read the specification, and there is a line that says:

Sample Rate Maximum.................................................. 2.00 MS/s single channel,
                                                                                     1.00 MS/s multichannel (aggregate)

When I tried to read 3 channels with sample rate 1 MS/s I get error: "ADC conversion attempted before the prior conversion was complete."
I did some tests and it seems  500KS/s is max for 4 channels and 250KS/s is max for 8. 

Am I missing something or this is how it works?

[Henrik_Volkers · Accepted solution]

aggregate means total number of samples.

This card uses a multiplexer to switch the AD converter between the channels. SO no really simultanious reading!

One channel , no switching , fast 2MS/s

more than one channel: about 500ns time needed to switch & settle between channels, so 1MS/s left in total, but you can read CH0,CH1,CH0,CH2 that would give you 500kS/s for CH0 and 250kS/s for CH1&2

[Dide_]

Aggregate - it explains everything 🙂

Thanks!