Integrated safety and control in the process industries can be implemented at a variety of levels, depending what individual companies find acceptable.
According to ARC Advisory Group Inc., in Dedham, Mass., there are four levels of integration: separate, interfaced, integrated and common. Dave Collins, product manager of machine safety products at vendor Schneider Electric, in Palatine, Ill., expands on these different levels of integration, adding one:
• Safety rated communication networks that tie the safety into the control system, but maintain a separate system • Communications networks rated for communicating both standard control and safety-rated information on the same communications cable at the same time • Safety-rated programmable devices that remain separate from the control system • Programmable logic controllers (PLCs) that are designed and approved for having both standard control and safety-rated control in the rack, and work together to manage these functions • Combinations of any of the above.
Related Feature - Integrated Safety Systems Winning OutTo read the feature article relating to this story, go towww.automationworld.com/feature-5491.
