Multifunction DAQ

Showing results for 
Search instead for 
Did you mean: 

Adjusting sampling frequency with Ni USB 8451

Hello all,


I have successfully created a program to collect data from multiple SHT 85 (temp/humidity) sensors using a NI USB 8451 DAQ (attached here).

Since all of my SHT85 sensors have the same Hex address, I am using a multiplexer to cycle through the different SHT85 sensors.


Sub VIs:

1.  to get Temp./Humidity data from SHT 85 sensor.

2.  to select multiplexer (I plan to add more multiplexers in the future to accommodate more sensors).


Is it possible to select/create a sampling frequency? Currently the sampling frequency is too high and I want to reduce it to say 1 Hz (1 sample/sec)


Currently I am utilizing a ms wait timer to delay the data recording/collection as per my required sampling frequency. The problem is, sometimes (when I set the sampling freq. = 1 Hz) the data gets collected at say 1s or 2s time intervals. Is there a better way to set the sampling frequency?


I have attached a LabVIEW code to collect data from 2 SHT85 sensor attached to 1 multiplexer.






0 Kudos
Message 1 of 3

Try using the 'Wait Until Next ms Multiple' instead of 'Wait ms' to make the logging interval better



Better to Close the session after the whole logging is complete





Semiconductor Validation & Production Test
Soliton Technologies
0 Kudos
Message 2 of 3

Thanks for your suggestions. However, this still does not solve my issue of selecting (user control) a specified sampling rate such as 0.5 Hz or 1Hz, etc.

0 Kudos
Message 3 of 3