• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 200 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS127L18EVM-PDK: Larger dataset capture

Shankar Bharathi Subramanian
Prodigy 10 points
Part Number: ADS127L18EVM-PDK
Other Parts Discussed in Thread: ADS127L18

Tool/software:

Hello, 

We recently purchased the ADS127L18EVM-PDK evaluation board and have been using the ADS127L18EVM-PDK-GUI to collect some data for our experiment.

I gave the following settings in the GUI to capture data at a lower rate.

Filter: Wideband filter

Clock: 3.2MHz and OSR: 4096, this gave me the data rate as 390.6 Hz.

My application demands a larger set of data to be captured. To test, I provided 1,000,000 samples under the Samples control field in the GUI, theoretically, it should have run for 42 mins but the adc ran just for 4 mins and stopped. However, the data log did consist of 1 million samples.

I also tried giving 40000 samples to capture, but instead of running for 100 seconds, it just ran for 10 seconds and stopped.

Would it be possible to explain the behavior here? Because I am a bit surprised here.

I should be able to run the ADC for at least 20 mins to capture the data that I am experimenting with and my data rate ranges from 5000 Hz to 300 Hz.

Looking for some help here.

Regards,

Shan

  • +1
    TI__Mastermind 47000 points

    Hello Shan,

    The Clock setting is only used with an external oscillator.  In other words, when connecting an external clock to the EVM, this CLK setting is only used by the GUI to calculate the expected data rate; it does not change the actual clock frequency on the evaluation board.

    However, the ADS127L18 does have an internal clock divider that you can set to 'Divide by 8'.  Setting this value to 'Divide by 8' and using the on-board 32.768MHz oscillator will result in a data rate of 500sps.  With 1Meg samples, this will result in approximately 33min of data collection.

    If you need an exact data rate of 390.6sps, then you will need to use an external clock.  Please refer to the ADS127L18EVM-PDK User's guide section 2.8 for details.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    Prodigy 10 points

    Dear Keith,

    Thank you very much for the reply. I shall try this method and I believe this one should meet my expectations.

    Thanks a lot again.

    Regards,

    Shan

  • +1 in reply to Shankar Bharathi Subramanian
    TI__Mastermind 47000 points

    Hello Shan,

    I did a little more digging, and there is a maximum timeout period for data collection, limiting the maximum data collection time to about 15min.

    Regards,
    Keith

  • 0 in reply to Keith Nicholas
    Prodigy 10 points

    Hi Keith,

    Thank you for the reply.

    In fact, we did get an error while we were trying to run the ADC for 30 mins.

     

    We got this error after about 16 mins, I think the 15 mins limitation explains this.

    We are working on our experiment to keep the data collection under 15 mins.

    Thanks for your support.

    Regards,

    Shan