Until now, the EN 954-1 had to be used to prove the fulfilment of the essential health and safety requirements specified in the Machinery Directive in the safety-related parts of control systems.
The standard, which was introduced in 1996, described the state-of-the-art technology at the time and covered the use of electromechanical and pneumatic components. Devices that can be flexibly configured with software were not, however, taken into consideration.
As the successor standards of EN 954-1, the harmonized standards EN ISO 13849-1 and EN IEC 62061 now describe the current state-of-the-art technology and provide guidelines for the design of safety-related control systems.
From categories to probabilities
This takes into consideration the probability of the occurrence of errors that lead to a failure of the safety function.
The resulting safety categorization is either a Performance Level (PL) or a Safety Integrity Level (SIL).
Two different standards
EN ISO 13849-1
EN ISO 13849-1 describes the design of safety-related parts of control systems and is based on EN 954-1.
EN IEC 62061
EN IEC 62061 describes the functional safety aspects of safety-related electrical, electronic and programmable electronic control systems.