Lengthy-Battery Life Move Meter Reference Design

The ability of ultrasonic circulate measurement is inside attain. Harness time-of-flight know-how to create low-power options for liquid and fuel circulate techniques.

Ultrasonic circulate meters are remodeling the measurement of liquid and fuel flows. These meters are important for income assortment, leak detection, and the conservation of pure sources, making them central to utility and industrial techniques for water, fuel, and warmth distribution. Mechanical circulate meters, which use transferring elements to measure fluid velocity, are the most typical kind. The MAXREFDES70 ultrasonic time-of-flight (TOF) circulate meter by Maxim Built-in makes use of piezoelectric transducers to ship and obtain ultrasound waves each upstream and downstream inside a pipe. The circulate fee will be decided by measuring the distinction within the TOF between the 2 instructions and making use of digital sign processing strategies.

Utilizing this reference design, design engineers can develop ultrasonic circulate meters that measure liquid and fuel circulate for functions corresponding to utility techniques for water, fuel, and warmth distribution. This design permits engineers to maneuver past mechanical circulate meters, utilizing piezoelectric transducers to measure TOF variations between waves travelling upstream and downstream in a pipe to calculate the circulate fee. 

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On the system’s core is the MAX35101, which integrates features for automated TOF measurements, together with ultrasound pulse technology, detection, TOF calculation, temperature measurement, and a real-time clock (RTC). The time-to-digital converter operates in numerous automated occasion timing modes, requiring minimal interplay from the host microcontroller, lowering total energy consumption.

The system operates on the TOF measurement precept. It options two piezoelectric transducers that perform as transmitters and receivers for ultrasound waves. The meter alternately transmits and receives ultrasound pulses between the transducers, with pulses travelling downstream and upstream. Ultrasound pulses journey quicker downstream than upstream, and the TOF distinction between these two instructions is proportional to circulate velocity. A bigger TOF distinction signifies quicker fluid circulate. When fluid circulate stops, the TOF distinction turns into zero. The MAX35101’s digital processing, analogue front-end circuits, and calculation algorithms be sure that TOF measurements are dependable.

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The gadget simplifies circulate computation with automated differential TOF measurement. Early edge detection ensures constant wave patterns and reduces errors. A built-in arithmetic logic unit calculates TOF variations, whereas a programmable receiver hit accumulator minimises the necessity for host microprocessor intervention. 

The system is managed by the EFM32ZG110, a 32-bit ARM Cortex-M0+ microcontroller working at 14 MHz with 32 KB of inner flash. The microcontroller communicates with the time-to-digital converter and an LCD module through SPI and GPIO pins. The MAX4721 is a low-voltage, low-on-resistance analogue swap used to isolate the LCD module’s SPI interface when the LCD is powered off, lowering present leakage to five nA and conserving battery life.

Maxim Built-in has examined this reference design. It comes with a invoice of supplies (BOM), schematics, meeting drawing, printed circuit board (PCB) structure, and extra. The corporate’s web site has extra information in regards to the reference design. To learn extra about this reference design, click on right here.