Smart Safety Boosts Productivity

System integrator Prodomax Automation Inc. needed to move beyondits relay-based safety control system. The hard-wired controls were slowing the company’s implementation of the manufacturing systems that it provides to Tier One auto suppliers. The Barrie, Ontario, Canada , company turned to new safety technology to reduce labor costs and implementation time.

The automotive industry has long been a first-adopter of factory automation, so it isn’t surprising that Prodomax used emerging technology to solve its time-to-market problem. Ordinarily, Prodomax takes 40 weeks to configure a new automation system. The company turned to an Ethernet-connected safety solution from Rockwell Automation Inc., in Milwaukee . Prodomax was able to connect all 33 robots in its system to a Rockwell GuardPLC 1600 controller.

The decision immediately reduced the wiring required by the old relay-based system, and it also offered needed flexibility. In the past, a safety trip would shut down all 33 robots. The new system stops only the robots in the immediate vicinity of the interruption, allowing the unaffected robots to continue operating.

Prodomax had high hopes the new technology would produce significant productivity gains. “The final result matched the intended result,” says Dave Thompson, manager of the Design Controls Engineering Group at the company’s Rochester Hills, Mich. , plant. “Our machines are faster and cheaper, and the safety is a lot more flexible. We can also get our product out to customers faster.”

The productivity gains from the new technology came in a number of areas. Prodomax cut five weeks off its 40-week implementation schedule. There was a 30 percent reduction in wiring, a 25-percent reduction in design and wiring time, a 20 percent reduction in overall labor costs and a 40 percent reduction in panel build time. That’s just the implementation savings. That doesn’t count the productivity gains its Tier One customer will experience.

New safety technology has gone global after years of development in Europe. In 2002, U.S. regulators opened up a flood of new safety technology. “In the past, safety had to be hard-wired. Safety wasn’t part of control,” says J.B. Titus, business development and safety standards manager at Siemens Energy and Automation Inc., in Alpharetta, Ga. “That changed in June of 2002. And that started the United Statesusing technology that was already mature in Europe.”

Prior to 2002, most U.S. plants operated on relay-based hard-wired safety tools. Since that date, U.S. plants have the green light to use Ethernet-based safety networks and safety programmable logic controllers (PLCs) that can be incorporated into the plant automation system. Add to that new developments in safe motion technology, and you’ve got the makings of an ongoing revolution here in automated safety.

The problem is, adoption in the United Stateshas been slow, mainly due to the conservative nature of plants and U.S.regulators’ lagging adoption of Europe’s safety standards. Part of the reason for the slow U.S. adoption is that new safety technology comes with a greater upfront cost. “It’s hard to convince people that spending a few hundred dollars more is the right way to go,” says Russ Wood, an application engineering manager at Omron Scientific Inc., a safety solutions company in Fremont, Calif. “I think the use of new safety technology is going to come, but we’re not there yet.”

生产力gains

As plants install smart safety technology, productivity gains are not a by-product. Productivity is the reason for adoption. Plants are implementing new safety technology to nab efficiencies. “Productivity is definitely the goal,” says Steve Freeman,director, Safety Systems Division, at Minneapolis-based vendor Sick Inc. “If you design the overall system to be safe and productive, you get a competitive advantage out of safety.”

Emerging factory safety technology was first developed in Europe, where the technology allowed regulators to change their notion of what operators can do in a plant situation. This gave operators more flexibility to deliver tangible productivity gains. “Productivity is one of the areas where Europeans have been ahead of the United States,” says John Wenzler,
corporate account executive at vendor Bosch Rexroth Corp., in Hoffman Estates, Ill. “If I have to move a jam in a machine, I have to shut down the line. In Europe, you can go into the safe area and move the machine in several different manners, either in safe speed, safe torque or safe direction.” With changed rules to accommodate safety technology, U.S.plants can now take Europe’s efficiencies.

One area of immediate savings companies 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. “你可以设置机器安全逻辑,如果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.

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