The emergency switching off circuit is often confused with the emergency stop circuit. The main differences lie in the reaction when the emergency stop or the emergency switching off pushbutton is operated. In the case of the emergency stop, the hazardous movements are stopped. In the case of the emergency switching off, power to the system is switched off, which is a requirement for electrical hazards (electric shock).
Both systems generally consist of one or more emergency switching off / emergency stop pushbuttons, which shut down the respective hazards via a safety relay. Emergency switching off or emergency stop devices are a requirement in Europe due to the Machinery Directive (2006/42/EC) and its harmonised standards EN ISO 12100, EN 60204-1 and EN ISO 13850.
Affected standards:
EN ISO 12100:2010 - SAFETY OF MACHINERY - GENERAL PRINCIPLES FOR DESIGN - RISK ASSESSMENT AND RISK REDUCTION
EN 60204-1:2010 - SAFETY OF MACHINERY - ELECTRICAL EQUIPMENT OF MACHINES - PART 1: GENERAL REQUIREMENTS
EN ISO 13850:2015 - SAFETY OF MACHINERY - EMERGENCY STOP - PRINCIPLES FOR DESIGN