• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 31 subscribers
  • Views 402 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.

PGA460: Is PGA460 suitable as a solution for Ultrasonic Wind Sensor?

user6286491
Prodigy 20 points
Part Number: PGA460
Other Parts Discussed in Thread: TUSS4470

The wind sensor has four integrated transmitter and receiver sensors  to test wind direction and speed。

The working frequency of the ultrasonic sensor is 200K., can 4 PGA460 be use as the solution?

  • 0
    TI__Mastermind 27780 points

    user6286491,

    The PGA460 may be suitable depending on your accuracy requirement. The PGA460's integrated 1MSPS ADC limits the step resolution of the DSP output to 1us.

    For example, consider these four time-of-flight cases at room temperature when the wind speed sensors are fixed 30cm apart.

    • No wind: 30cm / ( [ 331m/s + (0.6m/s/°C * 25°C) ] ) = 867.1us
    • 0.1m/s wind: 30cm / ( [ 331m/s + (0.6m/s/°C * 25°C) ] + 0.1m/s ) = 866.8us
    • 1m/s wind: 30cm / ( [ 331m/s + (0.6m/s/°C * 25°C) ] + 1m/s ) = 864.6us
    • 10m/s wind: 30cm / ( [ 331m/s + (0.6m/s/°C * 25°C) ] + 10m/s ) = 842.7us

    You'll notice that a wind speed of 0.1m/s requires finer step resolution than what the PGA460's ADC is capable of. You'll likely need to use a wind speed accuracy of +/- 1m/s for greater reliability. Also, the further the sensors are spaced from each other, the more likely you can enable higher resolution. We have not physically attempted to use the PGA460 as an anemometer, but it seems possible in theory.

    Four PGA460s, each with one 200kHz transducer is an ideal solution.

  • 0 in reply to Akeem Whitehead
    Prodigy 20 points

    Thanks for you reply.

    I understand what you mean， 0.1m/s corresponds to a response of 0.3uS（867.1-866.8)uS, but DAC only 1MSPS(1uS) ,so not ensure 0.1m/s accuracy.

    Generally, the accuracy for anemometer need reach 0.1m/s.

    If you use a traditional design,need to use a lot of separate components to build the drive circuit, excitation circuit, transmitter/receiver circuit,and caution to control the timing, so I am looking for any integrated solution, if PGA460 can not meet the design demand, do you have any other solutions recommended?

  • 0 in reply to user6286491
    TI__Mastermind 27780 points

    user6286491,

    We do have the new TUSS4470 front end driver and receiver ultrasonic IC available if you need higher accuracy than what the PGA460 can offer. This is because the TUSS4470 does not integrate any DSP functionality, so the accuracy is set and determined by external capture devices.

    The TUSS4470 offers two output modes:

    1. An analog output of the echo envelope waveform for you to capture using an external ADC for post-processing. You'll effectively need to compute the TOF based on your own threshold technique at the MCU.
    2. An echo interrupt pin to capture the START and STOP echo activity using a GPIO with timer capture. If don't want to worry about having to create your own threshold algorithm, this may be the easier approach to simply capture the delta between rising edge activity to determine the TOF.