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BOOSTXL-PGA460: BOOSTXL-PGA460 GUI with bi-static configuration

Jeff Iott
Prodigy 10 points
Part Number: BOOSTXL-PGA460
Other Parts Discussed in Thread: PGA460

Hi,

I want to evaluate the PGA460 part in a bi-static (separate transmitter and receiver) configuration. Section 2.3.2 Direct (Bridge) Driven of the BOOSTXL user's guide mentions the steps necessary to reconfigure the daughterboard for this configuration but there is no mention of how to use the GUI for this type of configuration. 

  • 0
    TI__Expert 8360 points

    Hi Jeff,

    Thank you for posting to the Sensors forum!

    Unfortunately, I did not get the chance to look at this today, but I will aim to provide a response shortly.

    Best,

    ~Alicia

  • 0
    Prodigy 10 points

    Alicia,

    I attempted using the burst and listen setting in the GUI and it seems to work so that question is answered. Not that I've had some time to evaluate the system, I have another question. What is the minimum range that can be detected with a transmitter/receiver configuration. Some off-the-shelf sensors are advertising a minimum range of 3cm but my setup seems to be limited to ~12cm. Is that right or am I missing something? I don't see any mention of minimum range in the PGA460 datasheet.Thanks.

  • 0 in reply to Jeff Iott
    TI__Expert 8360 points

    Hi Jeff,

    The measurement range of the PGA460 is not published as it depends on various factors (transducer frequency, excitation voltage, number of pulses emitted, etc.). Using the PGA460 in the manner explained in the User's guide does not yield a true bistatic system. This is due to the fact that a bistatic system requires a dedicated separate transmitter and receiver. When using the same device to receive and transmit internal noise from the transmission is coupled to the receiver path causing the system to behave like a monostatic system. The noise coupled is internally is not identical as if you were to only have one transducer, the ringing period is still smaller than what you would expect to see in a monostatic system. To achieve near 0cm measurements I would recommend the use of two separate Tx and Rx devices.

    There are other things you can do to  reduce the ringing period if using two devices is not an option for your system. Using higher frequency transducers will have a reduced minimum range, but they will also have a reduced maximum range. The larger the excitation voltage the longer it takes the ringing to decay. And you can also use some external passive components to optimize your ringing time.

    Best,

    ~Alicia

  • 0 in reply to Alicia Rosenberger
    Prodigy 10 points

    Hi Alicia,

    I should clarify my setup. I am using a separate transmitter and receiver with the direct drive section of the daughter board. The transmitter is connected to J9 and the receiver is connected to J11. It seems to be working with this connection strategy but the minimum range is only ~10cm. I have ~3" of separation between my transmitter and receiver which virtually eliminates physical cross-talk and I'm not seeing any in the data dump images. My desired range of measurement is 2cm - 2000cm. If I understand correctly, the time for sound in standard conditions to travel back and forth at that range is only 117uS. Can the PGA460 make that measurement? My issue may be caused by the physical separation and I will test that theory soon but I'd like to know if the IC has a limitation on the short range.

    On a related topic, I've not found a user's guide for the GUI, only the videos, and they don't answer some questions I have. For example, can the settings be saved such that I can recall them the next time I start up the GUI. Also, I'm not using preset 2 so I'd like to remove the P2 threshold from the graph. Finally, the measurement rate seems to be ~1 Hz. Can I speed up the measurement rate within the GUI and what is the fastest measurement rate with a custom microcontroller application? I need at least a 20 Hz measurement rate. Thanks in advance for your help!

  • 0 in reply to Jeff Iott
    TI__Expert 8360 points

    Hi Jeff,

    Jeff Iott said:
    Can the PGA460 make that measurement?

    To clarify, are you using 2 PGA460s in your bi-static configuration? As in order to be able to make a measurement that small, you would need to have your system setup in a bi-static configuration where you would be using 2 PGA460 devices (with one setup as the transmitter and the other setup as the receiver).

    Jeff Iott said:
    can the settings be saved such that I can recall them the next time I start up the GUI

    Yes, to save your settings you would need to:

    1. Go to the Memory Map
    2. Do a read of all registers
    3. Press the 'Save' icon
    4. Name and store the .txt in a desired location

    To recall these settings you would need to:

    1. Go to the Memory Map
    2. Press the 'Open' icon 
    3. Find and select the .txt file of register setting
    4. Pre-saved settings should now be loaded
    Jeff Iott said:
    I'm not using preset 2 so I'd like to remove the P2 threshold from the graph

    To remove P2 Threshold from the graph:

    1. Go to Data Moniter
    2. Click on 'Legend'
    3. Uncheck 'P2 Threshold'

    Jeff Iott said:
    Can I speed up the measurement rate within the GUI

    The measurement rate within the GUI is set to a default value.

    Jeff Iott said:
    what is the fastest measurement rate with a custom microcontroller application?

    The measurement rate is based on the recording time + device required processing time + time it takes to read the registers.

    Best,

    ~Alicia