Safety profitability starts with control system design

Nov. 1, 2006
"Despite the common thinking in a typical manufacturing culture, safety and productivity are not at odds," explained George Schuster, Rockwell Automation solution development manager, as he launched the Global Machine Builder (OEM) Forum in conjunction with Automation Fair 2006.

"Sure, to most production managers, safety means shutting down machines and reducing productivity. Safety is viewed as a cost and an introduction of risks. Companies often rely on luck to avoid injuries and then react to incidents as they occur," he said.


"Safety is a shared responsibility, and we're all stakeholders. A well-designed system improves both safety and productivity." Rockwell's George Schuster on how safety can increase productivity and provide a competitive advantage for machine builders and manufacturers.

"However, when systems are designed by integrating the safety functions of a control system with its non-safety functions, productivity actually improves," Schuster noted. "Safety improves floor space requirements, reduces injuries and lowers business costs such as insurance and workers' comp." Integrated safety systems help companies to simultaneously provide a safer workplace for employees and improve productivity through increased uptime. Costs also come down for activities such as installation and maintenance, he added.

He added that safety is a culture—a combination of people systems (procedures) and technologies (components and circuits). "It's a systematic approach, not a component-based approach. It's a life cycle from a system concept through risk assessment, design, build, start-up, validation, operations and decommissions. Safety specifications drive the safety life cycle," Schuster said.

Taking an integrated approach to designing systems in this safety life cycle includes using some of the new technology that Rockwell Automation introduced at Automation Fair. One of these new technologies is the CompactBlock Guard I/O designed for use with any safety controller that communicates on DeviceNet using CIP Safety for controlling and monitoring safety circuits. Guard I/O detects circuit failures at each I/O point while providing diagnostics to the controller. With CIP Safety, users can integrate safety and standard control systems by using safety and standard messages on the same wire.

Also, with the latest release of the Rockwell Software RSLogix 5000 programming software, the GuardLogix safety controller is designed for standard control (sequential, discrete, motion, drive and process) and safety control (SIL 2 and SIL 3) in the same system and a single platform.

The SmartGuard 600 safety controller 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 communication. Users can expand the number of safety inputs and outputs by controlling up to 32 Allen-Bradley Guard I/O safety modules. The built-in DeviceNet can simultaneously communicate the status of the safety system to standard PLCs and HMIs.

In addition, the new line of SensaGuard noncontact switches uses RFID technology for coding and inductive technology for sensing. It has a Category 4/SIL 3 rating switch and is TÜV functional safety approved to EN964 and IEC61508.