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ADS124S08EVM: Unable to read data from EVM board in Delta Sigma GUI

Rajaram Parsekar
Prodigy 20 points
Part Number: ADS124S08EVM

Hi,

I have configured EVM for a 2 wire RTD configuration. I have connected a 1k ohm resistor across J7 pin 1 and 4. And I am trying to acquire data from Delta sigma GUI. I am unable to read the data even though the hardware is detected.

My configuration are as shown in the image. When I click on collect data, I get a message saying "Write failed" in the status bar and no data is shown. Could you please help in rectifying the issue.

Thanks

  • +1
    TI__Guru** 112715 points

    Hi Rajaram,

    Welcome to the E2E forum!  I'm not entirely sure what is happening with the communication.  I have seen issues in the past where an ESD event has broken the USB communication by handling and connecting external devices to the EVM.  In this case you can try unplugging and re-plugging the USB cable to again reestablish communication.

    However, you do have some configuration issues.  The reference resistor is 1k and your resistance is 1k, so you will always see a full-scale reading.  Second issue is you are applying gain which will only make this worse.  I would suggest using a 100 Ohm resistor instead as the EVM was designed for PT100 sensors as opposed to PT1000.

    For the IDACs to flow excitation current the internal reference must be turned on even though it is not used as the ADC reference.  The IDACs require a known reference value and are trimmed to the known reference which is the internal reference.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 20 points

    Thank you Bob. My issue is resolved. Also we need to give a smaller sample number for data collection since the default value is too large and it takes a longer time for data acquisition.