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TDC1000-C2000EVM with air transducer MA40H1S-R

Jiaxuan Li
Prodigy 30 points
Other Parts Discussed in Thread: TDC1000-C2000EVM, TDC1000

Hello guys,

     Currently I am working on the TDC1000-C2000EVM with air ultrasonic transducer MA40H1S-R according to the user guide. The user guide only offers information for water ultrasonic transducer SMD10T2R111 in detail. So when I try the air ultrasonic transducer MA40H1S-R into this EVM, I failed.

    The specification of air ultrasonic transducer MA40H1S-R is that: Nominal Frequency is 40kHz, max Input Voltage is 6V.

     I use the internal clock in the board which is 8MHz. I config the software with the frequency divided by 256, then I get the frequency of 31.25kHz (which is the closest to 40kHz). The input voltage of the transducer is 5V in my board. I put one MA40H1S-R in the TX1 pin and select mode 0 with TX1 & RX2. Other configurations are default.

    I can detect the input pulse at TX1 and the START signal which are correct. However, I cannot detect any echo. There is no signal on COMP and STOP pins.

    I am not sure whether my configuration of TDC1000-C2000EVM is wrong, or the air ultrasonic transducer MA40H1S-R is wrong. Can someone help me? Or is there anyone who also uses TDC1000-C2000EVM with air ultrasonic transducer MA40H1S-R? I can find nearly no information about this on the Internet. I hope someone who can send me more information. Thanks.

  • 0
    TI__Expert 3350 points
    The TDC1000-C2000 expert will reply to your question, in the mean time, the external filter of TDC1000-C2000 is tuned for water application. For air application the external filter's center frequency needs to be changed to 1.5 kHz and the TX pulses need to be boosted to much higher voltages. Try TDC1000-GASEVM and TDC1000-BSTEVM (check TI website). The filter on the TDC1000-GASEVM is suitable for 40 KHz sensor ( centered at 1.5 kHz ) , the TDC1000-BSTEVM can boost up TX pulses to 30V.
  • 0 in reply to Bahram Mirshab
    Prodigy 30 points
    But according to the User Guide of TDC1000-C2000EVM, it says we have 2 options: SMD10T2R111 for water application and MA40H1S-R for air application. That is why we select MA40H1S-R together with TDC1000-C2000EVM. Is it possible to do some modification within TDC1000-C2000EVM to support MA40H1S-R? For the reason currently we have already worked on this board for some time.

    Now we are also comparing TDC1000-GASEVM with TDC1000-TDC7200EVM. In the User Guide of TDC1000-GASEVM, it says this board is suitable for gas flow measurement with the gas pipe transducers. We are not sure whether it is suitable for distance measurement with an ultrasonic gas transducer (not gas pipe transducers). And it seems that this TDC1000-GASEVM is a preview product which is not available to purchase at current.

    The TDC1000-GASEVM is compatible with the TDC1000-TDC72000EVM since all the components are the same. The difference is that TDC1000-BSTEVM can boost up TX pulses to 30V. However, the max input Voltage of MA40H1S-R transducer is 6V. There is no necessary to using TDC1000-GASEVM from our opinion.

    As a conclusion, we decide to change to TDC1000-TDC7200EVM for further evaluation if TDC1000-C2000EVM is not suitable (We are curious about how to change external filter's center frequency to 1.5 kHz). We are looking forward to hear from your suggestions.
  • 0 in reply to Jiaxuan Li
    TI__Expert 3350 points

    TDC1000-GASEVM has the same component as TDC1000-TDC7200EVM with the exception of external filter. It can be used with signal transducer as well if mode 0 is selected. TDC1000-C2000EVM external filter can be changed by changing the values of R27, C19, C20, R30. Attached is a top level TINA model of TDC1000 that you can use to redesign the filter. The values provided in the attached document will set the center frequency of the filter to 150 kHz. you may want to change C4 and C5 from 300 pF to 900 ohms resistors and use resistive feedback mode.

    4555.150kHz_center_frequency(resistive_feedback_mode).TSC