are taking is with installation costs. Plants are also taking savings by integrating safety with control. “Plants are saving time in installation and wiring,” says Skip Hansen, I/O Systems product manager at Beckhoff New Automation Technology, in
Burnsville, Minn. “There is also increased productivity when you use one software tool that unifies the whole system and you no longer have multiple safety and control systems.”
The 2002 change in
U.S.
safety standards was a breakthrough in allowing the use of safety PLCs and Ethernet-based safety networks. Those changes mean that plants are no longer tied to the relay-based hard-wired safety systems. Instead, plants can create smart safety networks that are connected by Ethernet. That also means safety networks can be incorporated into the automation control system. In the past, safety was run on a parallel system that operated separately.
Avoiding shutdowns
One of the most significant benefits from an Ethernet system with smart safety PLCs is that plants can grab diagnostic data from the safety network. “As far as productivity goes, if you have information coming back from safety devices, you can monitor what’s going on and replace things before they go down,” says Dave Collins, product manager for machine safeguarding products at Schneider Electric, an automation vendor with U.S. headquarters in Palatine, Ill. “That’s what people are looking for, solutions to avoid shutting down the line.”
Because safety can now be intertwined with the control systems, and because diagnostic data from the safety controllers can be collected and analyzed, plants can design their automation systems to incorporate safety technology. Safety no longer has to be an add-on separate from the production system. “Integrated safe motion technology flips the whole idea of how safety is integrated into the system,” says Sal Spada, research director for machine control and manufacturing processes at ARC Advisory Group Inc., in
Dedham, Mass. “Since you’re now working with software instead of relay contacts, you can increase the complexity of the safety logic.”
What that means is that safety on machines can be individually programmed to account for safe motion. That alone reduces many of the nuisance trips from relay systems. Users can also get faster response from safety controllers, which is a side benefit. “You’re substituting software logic for electromechanical devices, and that’s really big,” says Spada. “Safe motion is not the end-all and be-all, but it’s definitely a big part of safety solutions going forward.”
With the added logical intelligence of software, safety can be programmed in to operate very efficiently. “There are more intelligent ways to stop the machine,” says Helmut Kirnstoetter, product management director at B&R Industrial Automation Corp., in
Roswell, Ga. “You can set the machine with safety logic, and if something happens, logic drives the machine. You can save costs because you can stop the drive more quickly.”
While
U.S. plants have been slow to retrofit their safety tools, new plants are certainly adopting new safety technology. The productivity gains are widespread and measurable. Global manufacturers have been quick to adopt new safety technology, because standards are allowing global companies to use the same technology at their plants in Europe, North America and
Asia. The final result of new safety technology will be automation systems that are designed to incorporate safety devices and networks for a more productive and safer plant.
For more information, search keyword “safety” at www.automationworld.com.
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