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Safety controller plugs a gap

01 January, 2007

Safety controller plugs a gap

Rockwell Automation has unveiled a safety controller designed to fill the gap between safety relays and safety PLCs. The Allen-Bradley Smartguard 600 controller is said to reduce wiring and installation costs compared to relay-based systems, while linking closely with PLCs.

"Most companies today have two choices," explains Jeff Gellendin, Rockwell`s safety product manager. "They can either use safety relays where inter-wiring can quickly become very complex, even for basic safety logic — or they can implement a full-blown safety PLC system that can be expensive and time-consuming to program.

"The SmartGuard 600," he continues, "bridges the gap between these systems by providing a solution that is not only simple to install and easy to program like safety relays, but has been engineered to perform complex safety functions and seamlessly link to other intelligent devices on the plant floor — characteristics more frequently found in safety PLCs."

The compact controller (shown above) has 16 safety-related inputs, eight safety-related outputs, four pulse test sources, a USB port used for configuration, and a DeviceNet port that supports both standard and CIP Safety communications. The DeviceNet port allows users to expand the number of safety inputs and outputs by controlling up to 32 I/O safety modules. The same port can be used simultaneously to communicate the status of the safety system to standard PLCs and HMIs.

The controller can be used to provide safety interlocking with other Rockwell safety controls, and to distribute safety around a shopfloor. This facility could be used to close high-speed safety loops that might otherwise be too fast for a single safety controller on its own.