Repeated Data When Using Multiple Channels on My NI-9028

Updated Nov 11, 2019

Reported In

Hardware

  • NI-9208

Software

  • LabVIEW

Driver

  • NI-DAQmx

Issue Details

I have an NI-9208 and I am sampling data at 10Hz per channel over 11 channels. I have set the timing mode to high speed in the task in NI MAX but the data shows repeated values and I am not sure how to fix this.

Solution

Despite having set the task in NI MAX to ensure that the timing mode is set to high speed, the repeated sample values indicates the mode is not high speed but another option. It is recommended to programmatically set the timing mode within the program in LabVIEW by using property nodes.

Follow the guideĀ How to Switch Between High Resolution and High Speed ADC Timing in LabVIEW to implement this within the code.

Additional Information

The ADC conversion time for the NI-9208 in high speed mode is 2ms, whereas, in high resolution mode it is 52ms. This is the likely cause for the repeated values.