Managing Automation - February 2008 - (Page 29) — where the risks are very different depending on whether you stop motion or stop flow — can influence the way in which a vendor approaches safety. And even the vendors that come down on the side of integration in either the discrete or process environment do so with varying levels of intensity. According to ARC Advisory Group, a new class of safety system is emerging, which the consulting firm calls “same but separate.” There are four ways to set up a safety system, according to ARC (see chart, p. 28). The separate system, which has no connection to the process control, is built with separate operator interfaces, engineering workstations, and configuration tools, as well as separate data and event historians, asset management, and even network communications. Then there’s the three degrees of integration, which ARC defines as: interfaced (separate systems configured to enable data transfer); integrated (separate processors, but using similar architectures with some commonality in software; and common (one single box doing both safety and process control). The Dow-designed controller and the ABB AC800M HI (high-intensity) controller later co-developed with ABB fall into the “common” category, the highest level of integration. Indeed, integrated safety has become a business driver for manufacturers under pressure to lower costs and improve asset performance. According to Dow’s Gipson, there’s significant productivity potential associated with an integrated model that has a common architecture, language, and delivery approach. He can’t quantify the cost savings associated with it, other than to say that there is a lower learning curve. But the real value is in the heightened level of safety the company has achieved. “Between 1995 and 2005, we set aggres- “Of course, we have other technology that doesn’t have to put safety and process control into the same box.” — ABB’s Alicia Bauer sive targets for the reduction [of incidents] in all areas of safety performance,” Gipson says. “In some cases, we’ve a 90% reduction. In the area of plant operations and demonstrated safety performance of manufacturing facilities, automation is critical.” It’s difficult to say that the integrated safety process controller was completely responsible for the reduction in incidents, “but it was an enabler to get those results,” he says. According to ABB, which made AC800M HI generally available in 2005, the ability to streamline communications between the safety and process applications increases efficiency because they access the same memory and there are no communication delays between the applications. More important, “it meets all of the standards and requirements in IEC 65108 and TUV,” says Alicia Bauer, director of global marketing for control systems and products at ABB. “It is a very safe way to approach safety. That being said, of course, we have other technology that doesn’t have to put safety and process control into the same box,” she remarks, noting that many customers are not as comfortable as Dow is with the common concept. Still, it seems to be catching on; ABB has sold more than 800 AC800M HI packages across multiple industries, Bauer says. But just as not every manufacturer is comfortable with a common system, neither is every vendor. Most vendors are finding their footing somewhere in between separate and integrated, ARC says. Siemens falls under the integrated umbrella, as do Yokogawa’s ProSafe-RS SIS and Emerson Process Management’s DeltaV SIS, which the company calls “separate, but integrated.” “It’s separate because we have separate logic that is independent of the control systems, and we have an independent safety communications network At the same time, it is integrated with the Delta V system so that we can use an integrated set of configuration tools and a common operator interface,” says Mike Boudreaux, DeltaV SIS product marketing manager at Emerson Process Management. “[Rockwell’s] GuardLogix bolts right into the network, and, for electricians, it’s just like another PLC,” says Wayne Pearse, Smorgon Steel project electrical superintendent. Photos courtesy: ABB, Smorgon Steel 29 February 2008
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