• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 50 subscribers
  • Views 295 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

PGA309: With Absolute pressure sensor or negative pressure sensors - How to calibrate

Kyle Fricke65
Prodigy 10 points
Part Number: PGA309

Hi,

I am wanting to use the PGA309 with an absolute pressure sensor. Has any one used the PGA309 with one before. I am concerned in the calibration process. Typically with other digital pressure compensation method we would set up and perform 4 point calibration say at 30% and 95% pressures. These would be above atmospheric and the range would be absolute. So say 650 to 1050 mmHg. There will be no minimum pressure point to "zero" out the bridge. 

We plan to use a microcontroller to hold the memory and communicate directly with the PGA309 and not use an EEPROM. It will communicate via I2C. We would use the Vexc to drive the bridge and RT- will be used to sense the temp. of the bridge. Our sensor is remote and would connect to this bridge at a remote location. It would be compensated in this scenario.

Has anyone used the PGA309 in this situation before?

Thanks,

Kyle

  • 0
    TI__Expert 6250 points
    Hi Kyle,
    We don't have an example of PGA309 being used in this configuration, but what you're describing should be possible. As long as the inputs to the PGA309 remain valid over the range of pressures you're interested in, there shouldn't be an issue. What you'd essentially be doing is treating the bridge output at 650mmHg as the sensor offset or zero point, then calibrating the PGA309 gain and offset so that the range of sensor outputs that result from your 650mmHg to 1050mmHg pressure range result in your desired output range.

    If communicating with the PGA309 over I2C, you'll probably want to assert the PGA309's test pin. This will halt the PGA's internal state machine, preventing it from trying to reload settings from the external EEPROM, which would be absent in your configuration.
  • 0 in reply to Alexander Davis
    TI__Genius 11135 points
    Kyle

    We have not heard back from you so we will close this thread. Please reply if further discussion is needed.

    Thanks
    Dennis