Safety on Board: functional safety in drive systems speeds up engineering – Part 1

While international and regional standards for machine safety become ever stricter, manufacturers have to implement increasingly complex concepts more and more quickly. With its drive-integrated safety functions, Bosch Rexroth shows an economical way of ensuring maximum protection for people and machines while increasing productivity, ergonomics and efficiency in engineering.

 

Uncontrolled movements pose significant hazards. If processes dictate that operators have to spend time inside a machine, manufacturers must comply with the special safety regulations in the Machinery Directive 2006/42/EG or the relevant regional standards. Intelligent safety functions which are integrated into the drive system itself not only make it easier to carry out work in accordance with legal requirements – they can often prove to be a genuine competitive advantage too.

 

Trend towards more sophisticated safety functions

For most machine manufacturers and engineering offices, drive-integrated functions such as “safe stop 1”, “safe limited speed” or “safe direction of rotation” are established ways of ensuring safety in the workplace. Given the increasing requirements as regards complexity, performance and time to market, more sophisticated functions which can reduce standstill times and machine costs are now very much in demand too. Having predicted this development in the area of automation, Bosch Rexroth introduced the Safety on Board concept back in 1999. This concept which integrates safety functions into automation components has been expanded ever since. With the SafeMotion partial solution, a wide range of logic functions are integrated into the drive system itself.

With “Safety on Board”, users benefit from integrated, independent safety functions available on the complete range of drive systems. (Image source: Bosch Rexroth AG)

 

Greater flexibility with maximum safety

SafeMotion features in all IndraDrive drive families from Rexroth and includes not only the classic safe stop and movement functions but also numerous other certified functions, some of which satisfy the highest safety level Category 4, Performance Level e and SIL3. The more sophisticated functions include a safe door locking and SBS, the safe braking and holding system. The latter controls two independent brakes via redundant channels in the drive separately and monitors them so that people are safe if they spend time under gravity-loaded axes. In order to allow performance-enhancing functions for machine safety, SafeMotion supports a total of 16 safe absolute position areas and up to 31 safe cams.

 

Greater functionality and productivity with lower costs

The drive-integrated safety solutions from Bosch Rexroth not only make it easier to satisfy international standards. Thanks to their extremely quick reaction and selection times, they also allow machine manufacturers to increase personal protection and productivity to a new level with the help of efficient engineering. In conjunction with integrated instruction logic, the machines and part-applications can be made more compact and with fewer components. Export-oriented machine manufacturers also benefit from the wide range of supported bus systems complemented by a global service and consultancy network.

About the Author:

is product manager for electric drive technology at Bosch Rexroth. After studying electrical engineering at TU Braunschweig, he started in 1986 as development engineer at Bosch Industrial Equipment in Erbach / Odenwald. In 1993, he switched to product management for electric drives, where he is responsible in particular for drive-integrated safety technology.

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