Drives and Controls Magazine
Home
Menu

Safety controller plugs the gap between relays and safety PLCs

26 July, 2007

Rockwell Automation has launched a safety controller designed to bridge the gap between safety relays and safety PLCs. The Allen-Bradley SmartGuard 600 controller needs less wiring and costs less to install than relay-based systems, and is cheaper than a full safety PLC. It interfaces with PLCs, allowing standard and safety control systems to be integrated.

"Many companies today have two choices," explains Rockwell’s safety product manager, Jeff Gellendin. "They can use either 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.

Rockwell safety controller

"The SmartGuard 600 (above) bridges the gap between these systems by providing a solution that is not only simple to install and easy to program like safety relays," Gellendin adds, "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 new controller, developed for Rockwell by Omron and Sick, integrates 16 safety-rated inputs, eight safety-rated outputs, four pulse test sources, a USB port for configuration, and a DeviceNet port that supports both standard and CIP Safety communications.

The DeviceNet port will allow users to add more safety I/Os using up to 32 Allen-Bradley Guard I/O safety modules – the same type as are used in Rockwell’s GuardLogix systems. The port can be used simultaneously to communicate the status of the safety system to standard PLCs and HMIs.

A single software package – RSNetWorx for DeviceNet – is used both to configure the DeviceNet network and to program the SmartGuard controller.

Paul Davies, leader of Rockwell’s safety components and systems business in the UK, expects the new controller to be used for applications that would normally require at least four safety relays and three or more safety zones.