Capacitive fluid-level sensors with advanced software and customised interface

February 14, 2013 // By Julien Happich
Molex has released customised capacitive fluid-level sensors as a low-cost measuring solution with disposable sensors and reusable electronic circuitry for measuring fluid or granular material in non-metallic containers.

The patent pending sensor electrode design and configurable software provide higher accuracy with lower hardware cost and easier installation, claims the manufacturer. The custom-designed capacitive fluid-level sensors can be optimised for medical intravenous (IV) drip-feed bags, automotive fuel tanks, agricultural fluid tanks, hydraulic fluid and pump controls, beverage dispensing systems and other industry applications. Featuring multiple output interface options, including SB, I2C and discrete signals, the capacitive sensors provide a customised interface for virtually any application requirement. The sensors deliver 95 percent accuracy in auto mode and are 98 percent accurate when calibrated manually. The embedded software can be configured for maintenance-free auto-calibration or manual calibration to maximise sensor accuracy.

Equipped with flexible circuitry, which conforms to the container shape via pressure-sensitive adhesive, the capacitive sensors are easily mounted to the outside of a container allowing measurement of caustic fluids, in addition to granular and pulverised materials. The sensors can measure through almost any non-metallic material. Featuring solid-state capacitive technology with no moving parts, capacitive sensors eliminate problems with mechanical wear over time. Providing design flexibility, sensor circuitry substrate options include PCB, polyester flexible circuit and polyimide flexible circuit. A design can use a traditional PCB for a flat surface container or a thin, flexible circuit to accommodate curved surfaces or space-constrained applications. These fluid-level capacitive sensors can be mated with virtually any Molex interconnect or cable assembly.

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