At the beginning of 2012, the industry took a significant step in the continuing transition of safety standards that are emerging to define functional safety requirements for industrial machines. But while a large community of machine builders is already certifying their machines to these newer standards, a significant group seems to be lagging behind.
Current safety practices
According to a Design News survey, companies are certifying machines using a range of functional safety standards. A large group is certifying its machines using the ISO 13849-1 standard (42.9 percent), while others are certifying for NFPA (34.1 percent), IEC 62061 (29.7 percent), and the now-withdrawn EN 954 (15.4 percent) standard. More than half of the respondents (51.6 percent) are utilizing industry-specific safety standards such as Industrial Robots EN ISO 10218.
John D'Silva, marketing manager of Safety Integrated for Siemens Industry, told us:
What is very interesting is that more than 40 percent of the respondents reported they are already using ISO 13849 to certify their machines. In the past with new safety standards, we often found a cycle with customers of six to 18 months to understand the new standards and start talking solutions. This says that more customers are educated about the new safety standards.
The clear trend in safety logic devices is usage of safety relays decreasing, and the use of controller-based safety systems rapidly increasing.
(Source: Design News)
Tim Roback, manager of marketing of Safety Systems for Rockwell Automation, said in an interview:
On the question about the functional safety level used to certify machines, anyone who answered EN 954 has an opportunity to get aligned because that standard has been withdrawn. Those people would need to decide what standard would apply to them, and probably ISO13849 would be the first place to look. One thing that is interesting, encouraging, and that Rockwell would recommend is that if customers have industry-specific standards, also known as C Level standards, they should use them, and 53 percent are doing just that. Engineers should look for industry-specific standards if they have them.
Types of safety logic devices
When asked what types of safety logic devices are currently implemented on machines, safety relays was the most common response (59.3 percent), but both safety controllers including PLCs and/or standalone safety controllers (49.1 percent) and integrated Safety Control Systems (53.7 percent) were not far behind.
As far as the types of safety logic devices customers are implementing, while there is a fairly even balance between safety relays and integrated safety systems, Roback expects that use of separate safety controllers will continue to decline.