Omron Electronics said its range of E3ZM-B sensors use retro-reflective technology to automatically assess the quality of polyethylene terephthalate (PET) containers. The sensors can operate even in areas where dust and other contaminants are present, the company claimed. Ordinary photosensors depend on changes in light intensity for target detection but, with PET bottles, the change is only a few per cent. The differences makes the sensors hard to set up, and prone to drift out of adjustment if the operating conditions change. The E3ZM-B sensors instead use P-opaquing technology to measure the polarisation of the light beam, which typically changes by 75 per cent when a PET bottle enters the beam. "This makes E3ZM-B sensors easy to set up - after installation, the user simply presses a button with no target in place, and the sensor automatically sets the optimum switching threshold," Omron stated. No further adjustment or trials with sample bottles are needed and, after the set up operation the sensor will work with any type of PET bottle, no matter what size, shape or transparency, the company claimed. E3ZM-B sensors can continually monitor and adjust the intensity of the light beam using a special feedback system. The system ensures stable operation, even in the presence of dust and vapours or if the sensor lenses become soiled. "The need for frequent lens cleaning is, therefore, eliminated," Omron claimed. The E3ZM-B PET bottle sensors have an operating range of 100mm to 500mm and are housed in stainless-steel. Their operating temperature range extends from -40 ºC to 60ºC, the company stated. Omron Electronics Ltd is a UK subsidiary of the Omron Corporation.