TUSS4470: no echo from tuss4470 .

Part Number: TUSS4470

I am working with tuss4470 and the sensor B59070Z0285D121. the sensor is mounted on top of the 3mm iron sheet to detect the level of the container. we got the strange output from the VOUT pin without the echo but the same sensor was mounted on plastic we got the echo and the correct level but our application demand an iron wall. we need some help to solve the issue.
1)this sensor is suitable for our application?
2)our configuration is correct for this sensor?

my configurations

TUSS4470_WriteRegister(BPF_CONFIG_1,0x24);

TUSS4470_WriteRegister(BPF_CONFIG_2,0x00);

TUSS4470_WriteRegister(DEV_CTRL_1,0xB3);

TUSS4470_WriteRegister(DEV_CTRL_2,0x02);

TUSS4470_WriteRegister(DEV_CTRL_3,0x00);

TUSS4470_WriteRegister(VDRV_CTRL,0x0F);

TUSS4470_WriteRegister(ECHO_INT_CONFIG,0x18);

TUSS4470_WriteRegister(ZC_CONFIG,0xD4);

TUSS4470_WriteRegister(BURST_PULSE,0x08);

TUSS4470_WriteRegister(TOF_CONFIG,0x02);

VOUT

@OUTA

over 3 years ago

0 Jacob Nogaj over 3 years ago

TI__Genius 14686 points

Hello,

Thank you for your question and detailed description.

The issue is that the iron wall will significantly attenuate the ultrasonic signal for the transmit and echo return.

This is a figure from our Ultrasonic Sensing Basics app note , displaying the difficulty in sensing through metallic tank walls. In this case, only 1.4% of the transmit power is transmitted into the water.

There is no way to reduce the fundamental impedance difference between the materials, so the recommended solution is to generate more SPL via driving the transducer at a higher excitation voltage.

It is possible to evaluate the TUSS4470 with a transformer, but it will require external FETs and some other hardware changes to operate properly. Our TUSSS4440 device was specifically designed to be used in transformer driven applications for higher excitation voltages. I would recommend evaluation with the BOOSTXL-TUSS4440 EVM and a transducer in the 250+kHz range, B59070Z0285D121 should work well.

Finally, it is important to select a suitable transducer with proper frequency, and drive capability. The mounting of the transducer is also important to ensure the signal propagates through the metallic tank. This application report details the best methods for mounting of transducers: SNAA266

The current configuration registers look proper for the application.

Please let me know if you have any questions.

Thank you,

Jacob

0 mM over 3 years ago in reply to Jacob Nogaj

Prodigy 30 points

OK, Thanks. I have placed an order for a transformer -B78416A2386A003 for my application.

Now I am working on plastic container level measurement but I have a question, in my measurement, I have received multiple OUT4 interrupts so how can I take capture from it do you have any suggestions it this?.

0 Jacob Nogaj over 3 years ago in reply to mM

TI__Genius 14686 points

Hello,

For the interrupt, it will likely be necessary to use a microcontroller capture the desired interrupt and ignore the initial interrupt generated from the transducer burst.

If you find the interrupt signal to be too sensitive, it may be helpful to adjust echo interrupt threshold level:

This can help adjust the threshold to a point where only the return echo generates the interrupt signal.

Please let me know if you have any questions.

Thank you,

Jacob

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TUSS4470: no echo from tuss4470 .