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PGA309 Evaluation

Leni Skariah
Prodigy 30 points
Other Parts Discussed in Thread: PGA309EVM-USB, PGA309

Hi, I am trying to evaluate PGA309EVM-USB eval module refering the user guide http://www.ti.com/lit/pdf/sbou084 . The SW used is downloaded from http://www.ti.com/lit/zip/sboc320. I have 11 pressure points ( bridge output) for 17 temperatures and would want to emulate the sensor for all these pressure points. However, emulating the sensor  (using the jumper settings, not with the external sensor) i.e DAC voltage generation ( wrt 11 pressure points for 17 temperatures) using GUI is not so clear. User guide page number 49 ( of sbou084) says 'Enter raw bridge sensor data', there i am seeing the options to enter the offset i.e bridge voltage for 0psi and full scale ( for the maximum psi) in step 3. As per my understanding, it is for span and offset correction over the temperatures to have an accuracy less than 0.1%. In step 4, there is option to enter data for 0psi, full scale and midscale psi. This is for nonlinearity correction. I'm not finding any option to simulate the sensor for 11 pressure output over temperatures using GUI. Also, i didnt understand page number 33, what is this for ?? I refered the obsolete version PGA309DK,  how to emulate the sensor using the potentiometers and switches was explained in detail in it's user guide. Kindly clarify these points at the earliest.

Thank you so much.

Regards,

Leni

  • 0
    TI__Genius 12325 points

    Hi Leni,

    The sensor emulator tab does not have the functionality to enter that many data points at each temperature to achieve the granularity that you would like. This would have to be achieved by manually writing a text file. However, there is little point in entering that many data points for calibration of the PGA309. The performance improvement will be negligible above a standard calibration with 3 data points at 3 temperatures due to the limitations of the PGA309. Is there a specific reason why you are attempting to enter such a large number of data points?

  • 0 in reply to John Caldwell
    Prodigy 30 points

    Hi John,

    Thanks for your reply.

    I basically want to check if the accuracy is less than 0.1 % for all these 11 pressure points. I can try to have checks only for 3 points. However, i am not seeing an option to feed all these 3 pressure points via GUI. Is it via the load and temperature slider ? Please confirm.

    Also, how can i feed so many pressure points and temperature points using txt file ?

    Thank you

    Regards,

    Leni

  • 0 in reply to Leni Skariah
    Prodigy 30 points
    My question is how to generate the DAC voltage using GUI ?
  • 0 in reply to Leni Skariah
    TI__Mastermind 27715 points

    Hello Leni,

    I've deleted the other thread as it is a duplicate.

    Thank you for confirming your question. It is very straightforward to control the DAC voltage using the GUI.

    Click the "Run Sensor Emulator" button in the Block Diagram tab of the PGA309EVM-USB GUI. In this screen, you can adjust the temperature and % of applied pressure using the sliders. With these inputs, the GUI generates a DAC voltage based on the sensor nonlinearity file which you can create using the steps you mentioned earlier.

    See Slide 21 and 22 of this presentation: PGA309EVM-USB Calibration (4W Vout).ppt

    Best regards,

    Ian Williams
    Linear Applications Engineer
    Precision Analog - Op Amps