Ultrasonic sensors replacing photoelectric in many applications

Photoelectric sensors have, until now, been the most popular control devices for detecting conveyor transported items in packaging and labelling processes. Compact, easy to install and generally reliable they are highly suitable for applications where the target objects are opaque or translucent but with a lot of modern transparent packaging material they are unreliable. Transparent object sensors are retro-reflective photoelectric sensors, designed with extremely precise adjustment to allow them to sense clear objects but they are comparatively expensive, complicated and difficult to set-up.

Because ultrasonic sensors use sound waves to sense the position of the target and are unaffected by the degree of opaqueness of the container they are ideal to detect the clearest of targets and therefore can be used to replace both standard photoelectric devices and transparent object sensors.

Available from Contrinex in ‘diffuse’ and ‘reflex’ formats they are supplied in axial and right angle head arrangements with 200mm or 700mm ranges. The right angle head enables a very slim profile to be achieved when mounting on to the side of a conveyor thus reducing the likelihood of collision damage and preventing misalignment.

All sensors in the range are IP67 sealed, protected against overload, short circuit and incorrect wiring and have temperature compensation to ensure the sensing distance set is maintained despite temperature variations around the machine. A simple fourth wire teach-in facility prevents human interference with the setting of the sensing range but allows PLC controlled re-setting to accommodate multi-product handling on the same machine.