NI 9211 Sampling rate

[GracelynnMa]

Hi,

I am using NI 9211 together with cdaq NI 9717. I wonder what is the meaning of 14S/s "aggregate". As stated in the datasheet that the sampling rate for NI 9211 is 14S/s which also means the conversion time is 70ms per channel, but when I tested in the NI MAX by input "14Hz" in the timing setting , it shown with an error message: Error -200332 occurred at DAQ Assistant.

Possible Reason(s):

Specified sample rate is higher than the fastest rate supported by the device.

Property: SampClk.Rate
Requested Value: 14.0
Corresponding Value: 14.000002

Maximum Value: 7.142857

which make me curious about the maximum value on the sampling rate, shouldn`t it able to run 14S/s, instead of 7.142857S/s

Could anyone please explain the function of "aggregate" or suggest the corrective action. Thank you very much.

[RaviShrigiri · Accepted solution]

Hi,

Generally if its S/s/ch then its the sample rate for each channel.

If its S/s then its for all channels combined .I

if you use all the four channels then your sampling rate is reduced by 4. ( probably MUX used in back ground for switching between channels).However if you are only testing two channels then it should be reduced by 2.

[santo_13 · Accepted solution]

Hope this article helps - https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000kIz9SAE