Slow sampling rate 9214

[LabNewed]

Hello,

I am attempting to collect data using a compact DAQ 9174 with a 9214 high accuracy thermocouple module.  I am using 15 of the 16 available channels during my experiments.  I have used DAQ assistant to set up the module to collect at a rate of 4 Hz updating after each sample.  However, when I write my data, there are 4 entries per channel per second (which is what would b expected) but the values only update once per second (it shows the same value 4 times in a row then updates, shows that number 3 more times, update, 3 more times, and so on).  In the same while loop I am collecting data with a 9205 to read voltage inputs and am able to obtain 4 distinct vales per second with that module, Has this happened to anyone else?

[ThiCop · Accepted solution]

Hallo LabNewed,

Can you post some code illustrating your issue?

This way I can check what's happening in the code.

Are you using high-speed or high-resolution mode for your measurements?

If you're using the high-resolution mode, then this is expected behavior.

This is because the sampling mode is scanned (so it scans one channel at a time in a multiplexed way).

In high-resolution mode your bandwidth is 14.4 Hz (for 15 channels this is about 1 sample/sec), in high-speed mode this bandwidth is 80 Hz (>4 samples/sec for 15 channels.).

Please also take a look at the timing modes table over here: http://sine.ni.com/ds/app/doc/p/id/ds-314/lang/en

[LabNewed]

Thank you for your response, I was operating in High-Res mode.  I have made the switch and am now able to collect at my desired rate.

Thank you for your help.

[ThiCop]

Hello LabNewed,

Can you mark this question as solved.

This way other people having similar issues will be able to fastly find the right answer.