Machine safety solutions and legislation advice
17 April 2009
Like many activities within industry, safety is highly legislated. But end users, designers and OEMs can face confusion when confronted with a multitude of safety protocols & legislation that sometimes seem to have different requirements or even appear to contradict each other.
Machine safety solutions and legislation advice
Rockwell Automation is holding Functional Safety Seminars to clarify the current standards. The seminars are designed to give practical advice on changes in relevant EU Directives and legislation, application guidance, use of evaluation tools to simplify the use of ISO13849 and an opportunity to see and experience (via workshops) associated safety systems and products.
The concept of functional safety will change the behaviour of users and designers of automation systems, and why the publication of ISO 13849 has led to growing interest in performance levels and SILs (Safety Integrity Levels).
The standards that define PLs (performance levels) and SILs both cover safety-related electrical control systems, producing the same or similar results – albeit via different methods – giving users an option to choose the one most suitable for their situation. The outputs of both standards offer comparable levels of safety performance or integrity but each standard offers different solutions appropriate to their intended use.
Derek Jones said: "It is important for people to read both parts of EN954/ISO13849 as they provide extremely good design standards for safety systems. The main issue is that part one is well known, but part two is less well studied, and as it provides guidelines for validation and technological considerations, this is an oversight on the part of the many people who only read part one; the bigger picture is not always appreciated. One primary issue with these standards is that interpretation differs from designer to designer, mainly because of what they do not say as opposed to what they do say."
Jones concluded: "It is a very big step to move from categories to SILs, but at the present time the standards do not compete. The recent EN/ISO 13849-1 (2006) standard offers a transition path from categories to SILs via its own classification – PL (performance level) – and sits nicely in the middle between the two. It does have some compromises to simplify usability, but offers robust and inclusive requirements. With regard to simple systems, the requirements are very similar but as systems get more complex the gap widens."
The Functional Safety Seminars will also show attendees how to use SISTEMA (Safety Integrity Software Tool for the Evaluation of Machine Applications), a tool for the easy application of the Control Standard EN ISO 13849-1. The SISTEMA software utility provides designers of safety-related machine controls with comprehensive support in the evaluation of safety in the context of ISO 13849-1. The tool enables you to model the structure of the safety-related control components based upon the designated architectures, thereby permitting automated calculation of the reliability values with various levels of detail, including that of the attained Performance Level (PL).
The seminars will take place throughout the UK in May and June. The morning seminars will be followed by a Connected Components Exhibition and optional focussed workshops. Register your attendance at www.rockwellautomation.co.uk/safetyseminars
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