Safety on Board: Flexible and efficient with functional safety in drive systems – Part 2

With the dialog-based and universally supported engineering software IndraWorks, Bosch Rexroth ensures the shortest possible configuration and commissioning times for safety-related applications. Thanks to an extensive library of ready-made functional building blocks and numerous wizards which further reduce the engineering time, the programming work which previously took a considerable amount of time has now been replaced by a convenient selection and parameterization process. In order to make it easier for users to detect hidden faults, a dynamic online system tests all safety channels for possible faults independently in the background. As a result, manual testing is no longer necessary. And if servicing is required later on, the device can be replaced on the end user’s premises without a PC and with no need for another machine acceptance procedure.

 

Cost benefits thanks to integrated instruction logic

Because Bosch Rexroth equips its IndraDrive drive systems with safe logic components, many machines require fewer components and smaller machines can even manage without a separate control system for machine safety. With IndraWorks, “safe AND” with or without muting, “safe OR” and “safe inverting” can be configured individually for the relevant application. The integrated instruction logic in conjunction with the safe and direction-dependent cam areas also allow particularly time-critical applications. Depending on the current safe position of the axis, up to 16 different movement profiles which are to be monitored can be enabled automatically. If, for example, the light barrier detects that the operator of a servo press moves into the dangerous area when the stamp is descending, the drive system performs an emergency stop with no need to pass through the control system in the process. In turn, the emergency stop is muted depending on the angle of rotation during a risk-free start-up.

With a maximum of 31 safe cams and up to 16 safe absolute position ranges, SafeMotion offers machine manufacturers a wide range of drive-integrated safety functions. (Source: Bosch Rexroth)

 

Activation up to ten times quicker

The IndraDrive drive systems also provide various options for activating drive-independent safety functions. For particularly time-critical safety applications, extremely short, direct selection on the zone module via 24 volt signals is recommended. All axes involved can be activated in just 5 ms – around ten times quicker than if they were activated using the standard safe bus systems. Indirectly, this also allows a more compact machine design. For example, light barriers can be positioned closer to the dangerous movement even with the same approach speed.

 

Free selection opens up new markets

The IndraDrive drive systems still manage to support an unrivaled variety of bus systems. In addition to CIP Safety on Sercos which is used by the Rexroth SafeLogic or SafeLogic compact safety controllers, these include in particular PROFIsafe on PROFINET as well as Safety over EtherCAT and CIP Safety on EtherNet/IP. The facility to combine a direct and indirect selection makes it easier for machine manufacturers to gain access to a wide variety of sales markets while maintaining a full range of functions. For example, time-critical signals such as emergency stop can be connected directly to the drive system, while standard functions can run in parallel via the regionally preferred safety bus.

 

Standardized safety technology

Because Bosch Rexroth makes the drive-integrated “Safety on Board” solution available on all of the company’s drive units and motor families, machine manufacturers can standardize and consolidate their certified safety for all centralized and decentralized drive concepts. This applies to a whole range of systems, from the smallest IndraDrive Cs version with 100 W to the biggest IndraDrive ML drive system with 4 MW, from the control cabinet-based IndraDrive C and M series to the decentralized IndraDrive Mi drive systems without control cabinets and from the rotative and linear synchronous motor to the rotative and linear asynchronous motor. The MS2N servo motors also offer a SIL3 encoder for maximum safety.

 

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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