Light curtains and laser scanners are used where grids or partitions obstruct the flow of materials .On conveyor lines, transfers with a "muting" bridged i.e., silenced. Safe algorithms are better, says sensor manufacturer Sick, and offers intelligent Safe Portal systems.

Safety zones must allow certain objects to pass through the protective field while still reacting to the presence of people. Common implementations to date involve temporarily bypassing the non-contact protective device (NCPD) during material flow using additional sensors ("muting"). However, other methods exist that do not require this muting but instead use reliable algorithms to distinguish between material and a person.

Standard protective field

Thosethat do not trigger the safety function (= stop), but use a clever pattern recognition.

Every application is unique, and some solutions offer advantages over others; EN IEC 62046 allows for alternative solutions. Sick explores the potential applications in a wide variety of ways with its product portfolio – culminating in the Safe Portal system. This TÜV-certified safety system provides efficient access control at material transfer stations. It consists of two safety laser scanners and a function block for the Siemens S7 controller and meets the requirements of EN ISO 13849.

Safe Portal system. All images: Sick

The vertically oriented safety laser scanners, with their intelligent protective field evaluation, reliably and seamlessly secure applications up to PL d. Compared to other human-material differentiation solutions, this ensures uninterrupted personal safety in every situation. Simultaneously, objects with predefined contours can safely pass through the portal at any time.

The full article is available here.

 www.sick.com