explain DAQmx warning 200035 Clock rate less than minimum conversion rate?

[AzimJ]

I am sampling data at 1KHz on 3 channels using DAQmx read.  The DAQmx Read function is returning a warning that:

"Clock rate specified is less than the minimum conversion rate of the ADC. Your data may be invalid."

The hardware I have is a PCI-6115 multifunction DAQ from NI.  If I am interested in signal above 100Hz can I safely ignore this warning or do I need to sample at 50kHz and then have labview down-sample the data to 1KHz?

[Norbert_B]

You should attach your VI.

The error seems not to make much sense since it essentially says that 1kHz would be faster than the device can securely acquire.

Since 6115 can acquire up to 10MHz per channel, the error really is strange..... 

Norbert 

[AzimJ]

Thank you for your reply.  Let me clarify one point, I get the warning if I sampled at a low rate (say 1KHz), if I increase the sampling rate to 50kHz then the warning goes away. However, at 50KHz the rest of my application gets bogged down.

My data acquisition loop is a straightforward DAQ-MX taken from the examples, see attached.

[alcava.cr · Accepted solution]

Hi, according to the specifications you are bounded by a minimum sampling rate of 20 kS/s. Anything lower than that should give you the same error because this is a physical limitation the card has when using the internal sample clock.

[AzimJ]

I looked at the specifications on the website here which specifies the 10MS/s sampling rate which I assumed was the maximum and that there wouldn't be a minimum sampling rate. Also, that page did not mention a minimum sampling rate. Thanks for the additional information and specs you pointed to in the PDF document. I think that clears things up.