This standard is an application standard and in addition to the requirements for the selection and development of safety-related electrical, electronic and programmable electronic control systems (SRECS) includes an informative annex with a qualitative approach to risk assessment and assignment of a safety integrity level (SIL) which can be used on the safety-related control functions for machinery. This standard provides a machine sector specific framework for functional safety of a SRECS of machines. It only covers those aspects of the safety lifecycle that are related to safety requirements allocation through to safety validation. Requirements are provided for information for safe use of SRECS of machines that can also be relevant to later phases of the life of a SRECS. There are many machine characteristics where SRECS are employed as part of safety measures that have been provided to achieve risk reduction. A typical task of a SREC is the control of an interlocking guard that, when it is opened to allow access to the danger zone, signals the electrical control system to stop hazardous machine operation. Also in automation, the electrical control system often contributes to safety by mitigating risks associated with hazards arising directly from control system failures. This standard gives a methodology and requirements to : - assign the required safety integrity level for each safety-related control function to be implemented by SRECS; - enable the design of the SRECS appropriate to the assigned safety-related control function(s); - integrate safety-related subsystems designed in accordance with ISO 13849 ; - validate the SRECS. This standard is machine sector specific within the framework of the IEC 61508 standard series. It is intended to specify the performance of safety-related electrical control systems in relation to the significant hazards of machines. In addition to the current amendment, this edition also includes all corrigenda since the initial 2005 edition. The responsible committee is K 225 "Elektrotechnische Ausrüstung und Sicherheit von Maschinen und maschinellen Anlagen" ("Electrical equipment and safety of machines and mechanical equipment") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.