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TDC1000-GASEVM: TDC1000-GASEVM

peter mccormick
Expert 1100 points

Part Number: TDC1000-GASEVM

We cannot get the basic TDC1000-GASEVM to work through 4 inches of air.    Thanks, Peter

PDF HAS PHOTOS OF TEST ATTEMPT  www.lasso.com/.../LASSOULTRASONICSTEST.PDF

 

WE HAVE OTHER USONIC SENSORS BUT CANNOT EVEN GET THE OUT OF BOX TDC1000-GASEVM DEV SYSTEM TO WORK SO HAVE NOT TRIED OTHERS

 

WHY ALL OF THE RINGING? WE HAVE ADJUSTED REGISTERS AND READ MOST TI APP NOTES BUT NO IMPROVEMENTS.

 

COMP SIGNAL DOES NOT CHANGE AS SENSOR IS MOVED 1-4 INCHES FROM OBJECT. NO ECHO CAN BE SEEN, ONLY RINGING.

 

WILL THIS SIMPLY NOT WORK THROUGH SHORT AIR DISTANCES?

 

DO YOU HAVE ANY APP NOTES FOR 90KHZ OR OTHER FREQUENCIES TO ADJUST THE GAIN AMPLIFIERS ASSUMING WE GET THE BASICS TO WORK?

 

IS 2 METER SENSING THROUGH AIR FEASIBLE GIVEN THE PROPER SETUP, TRANSDUCERS, FREQUENCY OR EVEN  SOUND GUIDE TUBE?

 

PLEASE FEEL FREE TO CALL ANY TIME. WE ARE A HEAVY USER OF OTHER TI PRODUCTS.  THANKS

  • 0
    TI__Mastermind 31655 points
    Hello Peter,

    Which transducer are you using? In your PDF you say this is being run at 1Mhz. While this would not affect the ringing, the TDC1000-GASEVM has a bandpass filter between the output of the PGA and input of the comparator that is tuned for between 58Khz and 300Khz, which is a good range for gas measurements. Some amount of ringing is to be expected, but your scope captures do look out of the ordinary. I would first confirm that you are driving the transducer at its correct frequency.

    There are currently no app notes that specifically address your request, but the gain adjustment will have to be done according to your own application.

    The TDC1000 has an echo record length of 8ms, which equates to about 2.7m round trip in air (343m/s speed of sound), or 1.35m one way, so it will not be able to measure 2 meters.

    In general the TDC1000 is intended for liquid level, concentration, and flow measurement, or flow measurement in gas, but not necessarily longer distances in gas. I don't want to deter you from trying the TDC1000 in this application, but from your information it seems that the PGA460 ( www.ti.com/.../PGA460-Q1 ) may be a better fit.

    Regards,