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.

TDC1000: Tank material

Part Number: TDC1000
Other Parts Discussed in Thread: UCC27531-Q1

Hi,

I have a project to develop diesel level sensor for trucks, and I need a help. After testing the TDC1000-TDC7200EVM in the lab, we developed our own board with TDC1000 and a microcontroller. We decided to use UCC27531-Q1 to apply a higher voltage pulse to the piezo element. My circuit is similar to TIDA-0032, the main difference is I'm working with 15Vcc for the piezo element pulse.

In the lab, I tested the solution with two different materials, acrylic, and PVC, both tanks built with 3mm thickness. The result is very good.

When the liquid is 1m higher we have an echo with 1Vpp and noise is smaller them 150mVpp. It is very stable even when shaking softly the tank. When the liquid level is smaller them 100mm, the echo is higher them 2Vpp. In fact, the circuit is able to measure from 15mm to 1000mm with very good stability.

I started the field tests with diesel tank and I could not repeat the result.

In a stainless steel tank, with 2mm thickness, there is a noise around 40uSec even without water inside the tank. Is it a stainless steel echo interference? Is there any technique or tip to surround this issue?

After 60uSec I can identify the echo but it is only 300mVpp. As the water level becomes higher, I could not get the echo.

What can I do to increase the echo signal voltage?

The second kind of tank is built with HDPE (polyethylene high-density) with 10mm thickness. In this case, I could not get any echo, even lower than 200mm.

If I increase the voltage of the pulse the circuit will work properly for this material? Is there any other change I can do to make it work?

I hope you could help me with these issues.

If you need any other information, please, let me know.

Thank you in advance.

Artur

 

  • Artur,
    I have received your question & I will get back with you early next week.
  • Dear Bharat,

    I have some results of today tests to enrich our analysis.

    The channel 2 shows the signal in the COMPIN (TDC1000 pin 7).

    It is an HDPE tank, the thickness is 7 to 10 mm and it has 74mm of water. 

    Parameters:

    - Conf_00: 0x4A

    - Conf_01: 0x40

    - Conf_02: 0x20

    - Conf_03: 0x3

    - Conf_04: 0x5F

    - TOF_01: 0xE8

    - TOF_00: 0x1E

    - TimeOut: 0x67

    - ClockRate: 1

    As I told in the first message, we based our design in the TIDA-0032 schematic.

    Today we change the pulse voltage from 15V to 30V to elevate the voltage of the echo signal but the "UNKNOWN NOISE" grows up proportionally and its voltage is higher them the echo voltage.

    Do you know the reason of this unknown noise?

    What can I do to eliminate or minimize the noise?

    Do you suggest a different register setup for this situation?

    I'm waiting for your comments.

    Best regards,

    Artur

  • Artur,

    We have not run any setup using the HDPE pipe. The noise could be due to improper mounting of the transducer of the pipe or a reflection from the pipe itself.

    1. A band-pass filter centered on the transducer’s response can be used between each stage of the receiver path to reduce the noise.
    2. Try to setup the transducer with a proper mounting and dampers to reduce interference related noise.