Flow meter IC outperforms mechanical meters

The AS6031F1 is a complete hardware and firmware measurement solution for cold and hot water meters.

Drawing a continuous current of just 5 µA when capturing flow measurements at a rate of 2 Hz, or 15 µA at 8 Hz, the chip can operate for up to 20 years on the energy available from a single AA lithium battery.

The AS6031F1 includes an ultrasonic flow measurement front end with programmable amplifier, a low-power 32-bit processor and firmware for converting the sensor’s analogue outputs to precise measurements of cold water flow, volume and temperature.

This means that designers of water meters can use the AS6031F1 to easily and rapidly implement a complete new ultrasonic water meter without developing their own firmware.

The flexible device may be adapted to complement a range of typical spool piece designs. Users only need to characterise their spool pieces. It also offers firmware functions such as error handling and power-saving modes when the flow rate is zero. Users also have the option to add their own firmware code.

The chip provides a direct connection to ultrasonic transducers, and only requires the addition of a standard microcontroller to operate a water meter’s peripheral functions, such as a display and connectivity.

Designs based on the AS6031F1 can therefore be made more compact, with a lower component count than competing approaches that require a complex companion processor for elaborate calculations, and other external components.

The AS6031F1 allows designers to build robust systems which offer very accurate measurements of water flow and volume, making it suitable for use in water metering applications that are regulated by law. It measures the difference in the time it takes ultrasound waves to travel upstream and downstream, providing extremely repeatable, temperature-stable and accurate timing measurements.

The very high precision and stability of its flow measurements mean that it is able to detect water leakage rates as low as 0.5 litres per hour in a good DN20 meter, many times lower than the minimum water flow measured by today’s widely used mechanical water meters.

The device provides an SPI interface to an external microcontroller, or a pulse interface to emulate a conventional mechanical water meter’s signals.

Users of the Sciosense device may therefore replace their former mechanical flow measurement system with a modern non-invasive flow meter without the need to rewrite their application software.