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PGA460: Measurement of sludge level

Part Number: PGA460
Other Parts Discussed in Thread: TIDA-01386, TDC1000,

Hello everyone,
In my project, I want to measure the level of sludge accumulated in a large and deep tank, and I thought of using ultrasonic sensing for that, similar to the following product:

https://kansai-automation.co.jp/en/product/flow_meter_etc/sludge_interface.php

For that, I'd like to know which solution do you'd recommend for my project. I was thinking about using the PGA460 that has a 0.1 m to 10 m range, but it's recommended to use it in Air medium. Would it work for water? If so, what's the transducer's frequency should I use? I already read the SLAA732 Application Report and the FAQ but I still have doubts about it.
If the AFE PGA460 is recommended for my project, should I start with which EVM? (TIDA-01386?). In the end I want to design my own board using the AFE and a MSP microcontroller, and to send the distance data using ZigBee communication.

All suggestions are welcome!
Best regards
Lucas

  • Hi Lucas,

    Please see the following E2E post for a similar discussion:
    e2e.ti.com/.../2878365

    The PGA460 or TDC1000 are both suitable candidates for this type of application. Ultimately, you will need to conduct a feasibility analysis to determine which transducer frequency and drive strength is best suited for this application based on the tank depth and medium. The PGA460 and TDC1000 both support transducer frequencies between 30-480kHz. The TDC1000 can support even higher frequencies up to 4MHz, but the PGA460 has a more power integrated driver.

    If you are to use the PGA460, I recommend that you start your evaluation with the PGA460-Q1 EVM ( www.ti.com/.../BOOSTXL-PGA460 ).

    Higher frequencies are typically used for liquid coupled applications. Here is an example transducer I've successfully experimented with using the PGA460: www.prowave.com.tw/.../uwtx.htm
  • Thank you very much for your answer Akeem,

    Akeem Whitehead said:
    The PGA460 or TDC1000 are both suitable candidates for this type of application.
    I read that TDC1000 works better for 0.1m to 1m range, would it work for very deep tanks?

    Actually, I've been working with the TDC1000-TDC7200EVM for water level and flow measurement and I've had good results for clean water. But when I tried to measure level of sludge, there were some particles in the water so I couldn't have proper readings. Is there any way to solve this problem?

    Akeem Whitehead said:
    you will need to conduct a feasibility analysis to determine which transducer frequency and drive strength is best suited for this application based on the tank depth and medium
    I'm new to ultrasonics. Do you have any literature to recommend me?

  • Lucas,

    TDC1000 is not suited for large deep tanks and we do not have any specific data using TDC1000 on large sludge tanks.
    However ultrasonic is bound to have less accurate when there is non homogeneous mediums and any agitation in the liquid will affect the accuracy of the Tof measurement.
  • The TDC1000 AFE is not suited for deep tanks because of its power output? If so, would it be possible to amplify it?

  • Lucas,

    The TDC1000 can measure ToF of max 8ms. In water speed of sound is 1498m/s. So the max distance we can measure in water is around 6m.

    In case the tank is less than 6m deep we can use it. However please keep in mind ultrasonic is bound to have less accurate when there is non homogeneous mediums and any agitation in the liquid will affect the accuracy of the Tof measurement.