Xincrement doesn't agree with sampling rate

[AT1]

I'm using two PXI-5114 Digitizers that are being synchronized. I am trying to take 5 seconds worth of data.  I have the Sample Rate = 1e3 and the Record Length = 5e3. I only get about 1.3 seconds worth of data.  I looked at the Actual Record Length and the Actual Sample Rate outputs and they said the same thing that the front panel did. I then looked at the Wfm info output of the NiScope Multi Fetch Cluster.vi and it had the same Record Length but the Xincrement value is 262e-6. This corresponds with the measurements I am getting.  Any ideas?

Thanks in advance.

[Joe_S · Accepted solution]

Hi AT1,

Thanks for posting. What you are seeing is due to the fact that the minimum sampling rate of the PXI-5114 is 3.81 kS/s. The digitizer will coerce any value below 3.81 kS/s up to that value, therefore a record of 5000 samples will take 1.31 seconds to acquire. If you are looking to acquire 5 seconds worth of data, I recommend increasing the record length to around 19,050 samples, which should roughly correspond to 5 seconds worth of data. Let me know if this would this work for your application.

Regards,

Joe S.