Machine safety, in smaller packages

Control Engineering Europe 07 July 2008

The safety of machines and systems is one of the most important topics within the automation sector. The reason for this is the new Machinery Directive which will come into effect as of 29 December 2009.
On this date, the new Machinery Directive 2006/42/EG will replace the Directive 98/37/EG. All machines in the European market within the application areas of the directive must meet the specified safety requirements. Machine builders must expect fundamental changes. The machine directive stipulates a basic risk analysis for machines and systems, as well as risk minimisation if applicable. Appropriate technical safety measures can be derived from the results, and further defined. Safe operation of the machine in all of its operating modes and service-life stages must be taken into consideration, for example commissioning and automatic operation.
A further change will be the implementation of a CE marking for safety components. As there have been many discussions on the definition of a safety component, a list of components has been created. These include, for example, safety devices for detecting people or also emergency brake control units. A further amendment is the obligation to produce an assessment of risk as well as operating instructions for the technical documentation.
Only a few years ago, Pilz started the trend towards smaller, easier-to-program machine safety systems with its PSS Universal system. Today, many control and automation vendors have similar systems, and even servomotor and drive maker Baumüller has launched its own system, called b maXX-safePLC safety control, on the market.
At present, there isn’t much published information about it, other than it ‘helps increase safety and reduce complexity,’ and it can be used to satisfy SIL 3 requirements, but Baumüller is nevertheless proud that it won the ‘Red Dot’ design award.

PILZ’ NEW PROFISAFE INTERFACE
Pilz’ decentralized I/O-system PSSuniversal for safety-related and standard control functions now communicates via Profinet and Profisafe, thanks to this new bus interface module (far left in the photo). The new head module lets Profinet users connect the PSSuniversal into their systems, and use only one Profisafe address per station, so that safety settings for each device are made at a single point. Software to configure the Pilz system, called the PSSu Configurator, can be called up via TCI so that parameterising can be done on a Siemens Step 7 system.