MSP430™ ultrasonic sensing microcontrollers

Ultra-low-power SoCs for water, gas and heat meters

System-on-chip MSP430™ ultrasonic sensing MCUs are designed for high-accuracy water, heat and gas flow measurement applications. The MCUs feature integrated peripherals including an ultrasonic sensing analog front end, extended scan interface and DSP capabilities, and all MCUs feature a real time clock, LCD driver, 12-bit SAR ADC and comparator.

Ultrasonic sensing microcontrollers

  • High-precision ultrasonic flow sensing
  • Ultrasonic MCUs with integrated AFE
  • Integrated 8 MSPS sigma-delta ADC
  • Metering test interface (MTIF)

Ultrasonic design center for software and GUI

  • One-stop-shop for ultrasonic sensing development
  • Real-time waveform capture for added intellingence
  • Software library & GUI for ease of development

Ultrasonic flow measurement EVMs

  • Easy interface to ultrasonic transducers
  • Plug-in modules connects to add functionality
  • Power consumption analysis and LCD display
  • On-board programming and debug

Why ultrasonic sensing for flow meters?

Ultrasonic sensing uses the time of flight (TOF) of an ultrasonic wave within any liquid or gas medium and its dependency on the flow rate to measure and calculate volume flow. This technique uses the difference in the propagation time of the ultrasonic wave when transmitted into and against the direction of the flow. This technology is robust and accurate in measuring volume flow rates across a wide dynamic range. 

Ultrasonic flow meter features

Ultrasonic sensing provides: 

  • High accuracy <±1% of flow measurement
  • No moving parts or wear and tear for longer operational life and cost effectiveness with less service/maintenance
  • Resistant to vibration, infrared radiation and EMI

Works well on fluids including: 

  • Water
  • Oil
  • Paint

Works well on gases including: 

  • Air
  • Carbon dioxide
  • Oxygen
  • Methane

Our waveform capture-based approach for ultrasonic sensing

MSP430 ultrasonic sensing SoCs facilitate a unique waveform capture based technique, where the entire response of the transducer is captured in time domain for both the upstream and downstream conditions. Post-processing on these waveforms determine the differential time of flight (TOF). 

ultrasonic water meter diagram

Benefits of the waveform approach

  • Robustness to signal amplitude variation (transducer-transducer variation, different material compositions, high flow rates, noise, temperature variation, etc.)
  • Leak detection combined with very high accuracies at low-flow rates
  • Suppression of noise to achieve higher accuracy and reduced variations
  • 3V drive capabilities for transducers using standard MCU voltage levels
  • Ability to extend to material and composition analysis
  • Additional capabilities for meter diagnostics over time to:
    • Detect slow variation in envelop due to transducer aging, adjusts transducer-transducer resonant frequency variation
    • Eliminate periodic calibration over the lifetime of a product

Ultrasonic sensing solution analog front end (AFE)

The Ultrasonic sensing sub-system peripheral is anintegrated analog front end that can directly excite a wide range of transducers and has an integrated PHY for impedance matching. It also has an integrated programmable gain amplifier (PGA) and a high speed 8MSPS sigma-delta ADC in the receive section, which enables waveform capture in real time. 

Ultrasonic analog front end diagram

Features of the ultrasonic sensing AFE

  • Direct interface to a variety of transducers
  • Programmable pulse excitation for a wide range of transducers
  • PHY for transducer impedance matching
  • Programmable gain amplifier (PGA) for signal amplification up to 35dB
  • Real-time waveform capture using an integrated high-speed 8MSPS sigma-delta analog-to-digital converter (ADC)

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