• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 4 answers
  • Subscribers 31 subscribers
  • Views 224 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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: Transducer connection for mode 2 Application

Praveek GP
Prodigy 40 points
Part Number: TDC1000

hi,

In TDC1000 we are planning to use the mode 2 for water flow measuring application,

 it is mentioned in the data sheet, "TX1,RX2 is one pair & TX2,RX1 is another pair"  so, needs 2 transmitter and 2 Receiver, if the transducer has Transmitting and receiving capability means, we need 2 transducer,         could you help us how to connect the 2 transducer with the 4 pins?  can we short the TX1,RX2 pins and connect it with the +Ve wire of the 1 St transducer &  similarly for the second transducer?                                        (note: transducer have 3 wires 1:positive,2:negative,3:shielded wire)

  is it the right way? is my understanding is right? (note: transducer have 3 wires 1:positive,2:negative,3:shielded wire)

  • 0
    TI__Mastermind 22130 points

    Hello Praveek,

    Thanks for posting to the sensors forum!

    The TDC1000 is no longer the recommended device for flow measurements due a bug in the device that reduces the accuracy of the measurements. We typically recommend the MSP430-FR6043.

    To help clarify some of the questions above flow metering typically uses 2 transducers one as the RX and one as the TX, then the functions of the transducers will swap so the transducer that was used as the RX transducer before will be then used as the TX transducer and the TX will become the RX. On the TDC1000 for flow metering Mode 2 is used so Channel 1 = TX1/RX1 as a pair  and Channel 2 = TX2/RX2 will be a pair.

    You can short TX1/RX1 for one transducer TX2/RX2 for the other transducer and you connect the positive connection of the transducers to these pins. The negative and shield connections are grounded. I hope this helps!

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Prodigy 40 points

    Dear Isaac,

    In the data sheet it is mentioned Mode2 means  (Channel 1 = "TX1/RX1" and Channel 2 = "TX2/RX2"), but in the application information the transducers are alternatively connected (pair1:transducerA= TX2/RX1  and  pair2:transducerB=  TX1/RX2)
    is the channel and pair are Different or Same?
    could you clarify
  • 0 in reply to Praveek GP
    TI__Mastermind 22130 points

    Hello Praveek,

    The image seen in the application section shows TX1/RX2 and TX2/RX1 which can be used but it assumes mode 0 is used. Using these channels is perfectly okay, if mode1 or mode 2 are used for the device will require Channel 1 = TX1/RX1 as a pair  and Channel 2 = TX2/RX2. Mode 2 is typically used for flow metering because this is the only mode that supports automatic channel swap. If the other modes are used then the swap has to be done by the host. To summarize, the channels you need to use depend on the mode you will be using. This can be seen in table 8-3 on the datasheet.

    I hope this helps!

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Prodigy 40 points

    Hello Isaac,

             As you mentioned for mode 2 channel1=TX1/RX1 & channel2=TX2/RX2,  if we use mode2 for the water metering, do we have to short TX1 & RX2 pins for transducer 1 and  TX2/RX1 pins for transducer 2 in TDC1000.

    (then only RX1 can receive the TX1 Signal and RX2 can receive the TX2 Signal) is it right?

  • 0 in reply to Praveek GP
    TI__Mastermind 22130 points

    Hello Praveek,

    For flow metering if you are using mode 1 or 2 then you would short TX1 & RX1 pins for transducer 1 and TX2 & RX2 pins for transducer 2. If you are using mode 0 then you would short TX1 & RX2 pins for transducer 1 and TX2 & RX1 pins for transducer 2. 

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Prodigy 40 points

    Hello Isaac,

    as per your statement, we can short TX1/RX1 and TX2/RX2,

    But, Generally (mode 2), Waves from TX1 received by the RX1, similarly waves from TX2 received by the RX2.

    if we short like this (TX1/RX1 and TX2/RX2), How the Waves from TX1 will be received by the RX1 Directly for TOF Measurement?

     

    our design specs,

    Mounting: each transducer will be placed opposite facing each other, (in a slanting way)

  • 0 in reply to Praveek GP
    TI__Mastermind 22130 points

    Hello Praveek,

    During a flow measurement using mode 2 the channels are swapped. So during a "downstream" measurement transducer 1 would be used to generate the signal and transducer 2 would be used to receive the signal. So the TX pulse would occur on TX1/RX1 but since the channels swap after the TX pulse is generated it would be received by the RX transducer which would be transducer 2 on TX2/RX2. The inverse happens when measuring upstream with transducer 2 becoming the TX and transducer 1 becoming the RX.

    There are multiple ways to connect your transducers on the TDC1000 for flow measurements, the way I have explained it is what we have typically seen by other users. You are free to connect them using another method that makes sense to you if you would like to make sure you are connecting something appropriately feel free to make a post and we can confirm if it will work as expected or not.

    Best,

    Isaac