people on two systems,” says Mike Miller, business development for safety business at controls vendor Rockwell Automation Inc., in Milwaukee.

Cost is also a large factor for machine safety. An integrated safety and control system can come with higher initial costs. “The new integrated systems can be substantially more than the existing solutions, so a clear advantage in performance, functionality or business need must be identified,” says Dave Collins, product manager of machine safety products at Schneider Electric, another automation vendor in Palatine, Ill.

There are a number of savings plants are finding to offset the added expense of an integrated system. The savings come in implementation, staff reduction and increased uptime. “You can make a machine more efficient because of safety integration,” says Dan Hornbeck, safety development manager at Rockwell. “I’ve gone through my pneumatics and I’ve reduced air leaks and that has saved a ton of money. So integration helps the bottom line.”

Another benefit of an integrated system is that it can be replicated across many plants. Separate control and safety systems are not as portable. An integrated system can be exported to other machines or to additional plants. Best practices can be developed and implemented machine-to-machine, plant-to-plant. “Our safety control code can be exported out of one project to another machine,” says Kurt Wadowick, I/O products specialist at Beckhoff Automation, a Burnsville, Minn.-based automation supplier.

The integration of safety and control allows the control engineer access to the safety system. In many cases, the control engineering team works closely with the safety engineering team, and in some cases, the responsibility for safety passes on to the control team. “Moving to integrated safety is an education for all involved,” says Robert
Muehlfellner, director of automation technology at B&R Industrial Automation Corp.  a Roswell, Ga., automation vendor. “Control engineers didn’t used to worry about safety.

Even though the control engineer will have access to safety, many plants insist on maintaining separate teams. “I think there will still be a need for separate teams for safety and control,” says Wadowick, of Beckhoff. “Even though safety is in the control system, you still have to do hazard analysis and zone guarding, so if you open one part of a machine, the machine can still operate.”

Even though there is momentum toward integrated safety and control, many in the industry point out downsides to integration, especially with systems completely integrated in one box. “Some people are concerned about the failure of electronics,” says Tim Palmer, automation consultant at vendor Siemens Energy & Automation Inc., in Alpharetta, Ga. “The design is rock solid, but it still causes concern.”

One of the fears is that someone changing a control setting may inadvertently alter a safety setting. “If you go into your computer to change something and safety is in the same box, you’ve opened a Pandora’s box. How do you know if you’ve changed safety?” asks Charlie Fialkowski, national process safety manager at Siemens.

Fialkowski also points to the issue of cyber security. One of the potential challenges with integrated safety is the vulnerability to cyber attack. If safety is on the same network as control, it is potentially exposed to the Internet. “The process control is going to have some connection to the Internet, and that’s where the evil resides,” says Fialkowski.

While the safety standards have blessed integrated safety, some vendors take a decidedly strict view of control and safety separation. “Safety standard IEC 61508 states that the control system should be separate and independent from the safety-related system,” says Erik deGroot, marketing manager for safety management systems at automation supplier Honeywell Process Solutions, in Phoenix. “The more conservative users go for completely separated control and safety. If you use the same hardware, the control system should be treated as a safety-related system.”

However you look at it, the trend is strongly in favor of integrating control and safety. Whether it’s a matter of sharing data or running both control and safety from the same box, control engineers are seeing safety functions enter their realm. And the majority claim that safety has been enhanced as it merges with control.

Related Sidebar - Safety Integration Comes With Benefits
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Related Sidebar - Levels Of Integration
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