Power Electronics
Flow Meter Reference Design Provides Accuracy with Ultra-Low-Power

Flow Meter Reference Design Provides Accuracy with Ultra-Low-Power

An Ultrasonic flow meter reference design from Maxim Integrated Products, Inc. improves on traditional mechanical flow meters that measure water and heat usage with spinning wheels that can get out of calibration due to wear from friction and contaminants. This causes inaccurate meter readings and repeated, expensive on-site maintenance costs. Not only do these inaccurate readings reduce revenue, they also prevent leak detection, potentially wasting millions of gallons of clean water a year.

The MAXREFDES70# ultrasonic flow meter is the modern alternative to that old technology. This solid-state meter is 10x more accurate than mechanical meters, and 4x more accurate than competitive ultrasonic solutions. This accurate measurement is done without the use of heavy batteries, and the flow meter uses a single "A"-size battery that can last up to 20 years. Measuring as little as 0.5 liters of water per minute with better than 1% accuracy, its fast ultrasonic pulses can be customized to the pulse frequencies required by flow conditions. It can detect even minor leaks that the mechanical meters will never find. With no moving parts.

MAXREFDES70# flow meter is highly resistant to contaminants, subject to less wear, and requires virtually no maintenance. It features no compromises, as it maximizes uptime and provides the most accurate data possible. In this era when natural resource consumption must be carefully managed, this complete, ready-to-use flow meter reference design lets utilities and other industrial flow-measurement applications get to market quickly with the necessary accuracy and precision.

At the heart of the MAXREFDES70# reference design is the new MAX35101, a complete time-to-digital converter with analog front-end (AFE) that measures the difference of upstream and downstream ultrasonic pulses. Supporting flow measurement at low rates (< 30 l/hr), the MAX35101 offers the highest time-to-digital conversion accuracy (20ps) on the market today.

The MAXREFDES70# system, including circuit board with the MAX35101, two RTD probes, and spool body, is available for $500 each. The schematics, layout files, and firmware are free and available for immediate use.


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