By Jim Montague, Executive Editor
Some changes are glacially slow. Others happen fast like an earthquake. But it's usually the changes you already should have dealt with that sneak up and surprise you—like a machine safety standard that was postponed for two years before finally going into full effect.
That's right, the EN-954-1 machine safety standard was replaced by the ISO 13849-1 and IEC 62061 standards on Jan. 1. Where the old standard generally was prescriptive, the new ones reportedly require more proof of compliance. So, while use of programmable safety controllers has been increasing since the revised NFPA 79 standard began allowing safety and control communications on the same physical network in 2007, it's pretty certain that ISO 13849-1 and IEC 62061 will cause demand for these components to skyrocket.
"Implementation of programmable safety controllers, such as our GuardLogix, has been increasing steadily since it was introduced in 2005, but increasing competence, mainstream awareness and retirement of traditional expertise is bringing us to the end of that hockey stick on the graph where really rapid adoption happens," says Tim Roback, marketing manager for safety systems at Rockwell Automation (www.rockwellautomation.com). "We'll also see more demand for safety tools and services because users are waking up to understand that safety can help improve performance, cycle times and configuration. So, in March, we're going to introduce our PointGuard analog input safety module for process applications."
Robert Muehlfellner, automation technology director for North America at B&R Automation (www.br-automation.com), adds, "Changes in the standards already were forcing builders to reassess their machine safety, but ISO 13849-1 and IEC 62061 are stricter, and so even more of them are beginning to design programmable safety into their machines. Because programmable safety can be extended to safe speed and motion control, it can jog machines within safe axis limits, directions and speeds, and allow operators to safely clear jams in minutes instead of hours."
Sergio Aguilar, product manager at Omron Scientific Technologies (www.sti.com), adds, "Programmable safety controllers are gaining safety control market share rapidly because they're more flexible, lower-cost, easier to troubleshoot and can achieve higher safety levels. By selecting a program in a programmable safety controller, a machine can perform tasks that would be hard or impossible with hardwired components. A machine and its safety system also can scale up or down much easier with a programmable safety controller than with hardwired safety relays. In addition, we find there can be savings when replacing as few as two safety relay units with a programmable safety controller, and it's simpler to troubleshoot because it has built-in diagnostics, and can detect which device has failed via PLC and HMI connectivity. Finally, because the new version of ISO 13849-1 focuses on machine reliability and safety functions, users might be able to use programmable safety controllers to attain higher performance levels by allowing greater diagnostic coverage, or creating a different category level based on the input configuration of wiring in parallel, as compared to wiring in series."
Aguilar adds that Omron STI is simplifying the connections between its safety controllers and various PLCs via EtherNet/IP, Omron's FINS protocol for Ethernet and RS-232. "We've also just released our NJ machine automation controller," he says. "The first version integrates logic, motion and vision into one platform, and future releases will integrate safety directly."
There's no programmable safety controller that's as inexpensive as a conventional safety relay, "so the higher-end products have to come down in price," adds Helge Hornis, manager of the Intelligent Systems Group at Pepperl+Fuchs (www.pepperl-fuchs.us). "And we're seeing safety devices getting cheaper. In fact, we're currently introducing a safety controller that's competitive as soon as a machine requires just two safety relays. Pepperl+Fuchs also will release a safety controller that starts out as a standalone device for the smallest machines, but can expand if added safe inputs and outputs are needed, become part of a safety network, and can ultimately transmit safe information between multiple safety networks."