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Original question:

ADS1262 - 4 wire bridge measurement

ADS1262EVM-PDK: ADS1262 - 4 wire bridge measurement

Gianfranco Schwengle
Prodigy 10 points

Part Number: ADS1262EVM-PDK

Few things I am not sure about is possible to do AC excitation with ads1262evm-pdk. If yes how can this be configured in the software? I know for hardware there need to be four analog switches configured to switch the polarity of the supply voltage. Another thing that confuses me are the modes of operation. I am under the impression that input chopping and the digital filter cannot be done together. Can anyone help?

  • 0
    TI__Mastermind 44600 points

    Hi Gianfranco,

    Welcome to the TI E2E Forums!

    With the provided ADCPro software, I don't know of an easy way to implement AC excitation...
    The problem is that ADCPro only lets you configure the ADC registers once, and then collect a block of data for that configuration. To do AC excitation with the ADS1262 you'd need the ability to reprogram the device registers while collecting data, and then you need to do some basic math operations to compute the average result (see the TIPD188 reference design for more details). However, unfortunately ADCPro lacks the ability to script this type of behavior...

    Alternate solutions:

    • The ADS1262EVM-PDK LabVIEW source code is provided and can be downloaded at http://www.ti.com/lit/zip/sbac160. If you have a LabVIEW license, then you can download the LabVIEW source code and modify the LabVIEW code to implement the required sequencing and math operations.
    • If you're able to get a hold of the MSP430F5529 LaunchPad (used in TIPD188) and jumper wire it (with short connections) to the ADS1262EVM daughter card, you would likely be able to download the TIPD188 firmware code and modify it to implement the AC excitation however you would like.

    • Another option would be to check out the new ADS1261 and ADS1261EVM. This device is very similar to the ADS1262; however, the non-overlapping GPIO signals are automatically generated by the device and you would be able to do AC excitation without the need to stop and reprogram the register setting between data readings. Also, the averaged result is calculated internally so AC excitation is much more streamlined and requires no additional overhead by the microcontroller.

    I hope that helps,
    Chris