Safety Components: Smarter Machine Technology Drives Safer Bottom Lines

Safeguarding machinery while protecting the workers: What could be simpler to comprehend about design and use of machine-safety components?

Aw 1401 1010 Infra
Some current trends reveal that industry understands. For example, making safety an integral part of the design is one trend that Jürgen Bukowski notes. “That is not only to switch something off because a worker is there doing maintenance, but also to look intelligently at safety,” says the program manager in the Safety Systems Group with automation components supplier Sick Inc. (www.sick.com), Minneapolis. Risk assessment—a tool more established in Europe—facilitates safer design, he states. And by using microcontrollers, designers and manufacturers enhance reliability by allowing metrics such as mean time to failure, he adds.

Two other recent trends that will extend into the near future include software-based products and network-integrated products, Frank Webster observes. “As processors get more powerful, smaller and cheaper, we find we can make more complex devices at lower costs,” suggests the vice president of standards and special projects at Omron Scientific Technologies Inc. (www.sti.com), a Fremont, Calif., automation products vendor. But is complex always better? While saying that it isn’t, Webster notes that higher-capability and faster processors make it possible to have a single box or cabinet. That enables fewer and smaller cabinets, and reduces power requirements, he notes.

However, more complexity increases risk of having design errors, Webster remarks. “For example, when most safety functions depend on software, it becomes very critical that the software is well designed and verified.” To help compensate for these needs, he mentions two relatively new and “roughly equivalent” functional safety standards being used now: “ISO 13849: Safety of machinery—Safety-related parts of control systems—Part 1: General principles for design,” published by the International Organization for Standardization (ISO, www.iso.org); and “IEC 62061: Safety of machinery—Functional safety of safety-related electrical, electronic and programmable electronic control systems,” published by the International Electrotechnical Commission (IEC, www.iec.ch).
 
A member of the working groups that wrote those standards, Webster says that ISO 13849’s features allow use of hydraulics and pneumatics as well as electrical devices, “types of energy very common in industrial machines.” However, the IEC standard is not familiar to machine builders, but “it’s very familiar to high-level control designers; for example, with programmable logic controllers.”

Human/robot collaboration

Closer human-machine collaboration represents yet another trend that Webster sees. In robotics, he believes that means having proximity sensors, or proxes, in the robots. “The other sensor technology in which there’s a great deal of research is vision-protection devices.” He predicts that general-purpose vision-based safety sensors will grow in popularity in the human-machine collaboration arena, where material-handling and manual operations exist in a process. “The most vivid example: a robot moving a heavy piece of material and a human attaching something to it.”

Calling overall robot-human collaboration a “hot” trend, Eric Hollister notes that the concept of humans working intimately with robots, as opposed to being separated by fences and guards, has been a theoretical topic for “quite some time.” ISO’s new standard “10218—Robots for industrial environments—Safety requirements”—addresses such collaboration, adds the product manager with industrial safety products vendor Pilz Automation Safety L.P. (www.pilzusa.com), Canton, Mich.
 
And to address safety in robot cells, Siemens plans to release in the United States, by Dec. 1, the Sirius safety relay 3TK2810-1 device for speed monitoring, states John D’Silva, target-market consultant for safety with Siemens Industry Inc. (www.siemens.com), Norcross, Ga. “It facilitates simultaneous monitoring of standstill, set-up and automatic speed. It also features a function for interlocked protective door monitoring.” The device can have both encoder and prox in the same box, he comments.
 
Despite trends or technology, “the ultimate goal is to protect every operator and maximize efficiency,” Sick’s Bukowski emphasizes. And underlining that “safety is elimination of risk,” Omron STI’s Webster thinks that “safety is already pretty good.” Technology is getting smarter, he adds—and “smarter means you can increase production without increasing risk.”

C. Kenna Amos, ckamosjr@earthlink.net, is an Automation World Contributing Editor.

Sick Inc.
www.sick.com

Omron Scientific Technologies Inc.
www.sti.com

International Organization for Standardization, ISO
www.iso.org

International Electrotechnical Commission, IEC
www.iec.ch

Pilz Automation Safety L.P.
www.pilzusa.com

Siemens Industry Inc.
www.siemens.com 

Subscribe to Automation World's RSS Feeds for Columns & Departments

More in Control