Contrinex don’t need to soft-soap hand-wash manufacturers about performance of metal M18 Photoelectric Sensors

The past couple of years have seen an explosion in the popularity of non-contact hand-washing units. The manufacturers of these soap and water dispensers need robust, reliable and affordable sensors to detect the presence of the user’s hands. Traditionally these systems have used two sensors for accurate triggering, but a single Contrinex M18PA Reflex Background Suppression Photoelectric sensor, available from PLUS Automation, can work reliably and save space and cut costs. The customer wanted a small dual-output sensor capable of withstanding mechanical shocks and resisting fluid ingress while offering an attractive price/performance profile.

Customer application

Hand sanitisation has become a hot topic in washrooms as a method of protection against COVID-19 and so a permanent feature of everyday life. Automated, non-contact operation is the norm for speedy, safe hand-washing, using either soap and water or an alcohol-based sanitiser. Manufacturers of these dispenser systems need robust, affordable sensors to detect the presence of a users hands to trigger delivery of soap, water or sanitiser.

Soap-and-water dispensers have dual delivery systems, traditionally requiring two sensors for accurate sequential dispensing. The increased interest in non-contact systems has created the opportunity of a new market for lower-priced dispensers and so there was an interest in the feasibility of a single-sensor system, saving space and cutting cost. A key requirement is a dual-output sensor with a delay function, allowing a programmable interval between soap- and water-dispensing.

The application also creates additional constraints because the aesthetic design of the dispensing head limits the space for the sensor and the need for ingress protection against liquid soap, water or sanitiser. Cost constraints also exert significant influence in sensor selection, limiting the choice to devices with an acceptable price/performance profile.

Customer Solution

High-performance, small and robust, Contrinex’s new metal-bodied M18M photoelectric sensors fulfil all the dispenser manufacturer’s requirements. The diffuse mode sensors with background suppression are practically insensitive to a target’s size, colour, shape and texture, and provide a long sensing distance of up to 250 mm, ideal for the application.

Fitting an M12 right-angle connector extends the compact 33 mm long sensor to only 55 mm including the connector. The sensor is therefore, able to fit beside the soap and water nozzles in a typical, tightly packed dispensing head.
Contrinex’s ASIC technology provides best-in-class sensing distances, and the rugged IP67 rated stainless-steel (V2A/AISI 303) housings and shatter-resistant PMMA optics provide excellent protection against mechanical shock and fluid ingress.

The sensor’s multi-mode IO-Link functionality provides two discrete outputs following the detection of a target. An initial one-shot output delivers a single pulse to trigger the soap dispenser, while a second, delayed pulse initiates and maintains the delivery of water for a user-defined period of time. IO-Link also allows real-time access to process data as well as additional functionalities that include sensitivity adjustment, event flags and sensor-temperature measurement.
Designed with the needs of OEMs and system integrators in mind, Contrinex M18M metric-threaded metal-bodied photoelectric sensors are not only affordable but meet designers’ needs for a robust, versatile solution with best-in-class service life. They represent exceptional value for money while offering a price/performance profile that exceeds expectations. Customised versions with bespoke functionality are also available for specialised applications.

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