Space-saving safety controller needs no software

Sick has developed a modular safety relay system that allows users to implement complex safety logic without needing software. Instead the logic functions for the UE410 Flexi series — such as AND, OR, bypass or muting — are set up using program switches on the front of the modules. The result, says Sick, is a space-saving system that reduces wiring dramatically.

Items in the modular system include main controllers, expansion controllers, various dual-channel safety input and output modules, and DeviceNet and Profibus interface modules. The modules can be combined to provide bespoke safety logic systems supporting up to 104 I/O.

Until now, says Sick, users have needed different safety relays for applications such as two-hand controls, interlock switches, light curtains and emergency stops. The new system can handle all of these functions, and combine them logically.

The system saves money and space in several ways. The controllers handle the functions of two safety relays in a 22-5m-wide housing, and by supporting up to eight inputs, can replace four extra safety relays. Because most types of safety device can connect to the system, the number of different relays needed for an application is reduced substantially, saving on spares and panel space.

Also, because the logic blocks are chosen using pre-configured functions via the programming switches, the wiring normally needed to achieve this logic disappears.

In one of the system`s first applications, a Finnish manufacturer of film wrapping machines, Halioila Oy, has found that instead of the six inter-wired safety relays, occupying 225mm of DIN-rail space, that is was using previously on its machines, it now needs just two devices, taking up 45mm.