(Translation of German Websites)
Already the 1989 edition of the European Machinery Directive said: Despite an E-Stop a so-called Normal Stop is required. However, until now the Standards für industrial robots payed not much attention to this fact. The new EN ISO 10218- series for industrial robots will change this situation. We will tell you what’s behind.
The requirements of Machinery Directive regarding Normal Stopping have widely not been changed since 30 years:
- Machinery must be fitted with a control device whereby the machinery can be brought safely to a complete stop.
- Each workstation must be fitted with a control device to stop some or all of the functions of the machinery, depending on the existing hazards, so that the machinery is rendered safe.
- The machinery’s stop control must have priority over the start controls.
- Once the machinery or its hazardous functions have stopped, the energy supply to the actuators concerned must be cut off.
Why the standards did not require such device before? Probably, because complex machinery like industrial robot systems generally already provide buttons generating such a stop. Therefore, a real violation of Machinery Directive probably never took place.
Nevertheless, the new final draft ISO FDIS 10218-1:2024 now takes on board this requirement of Machinery Directive. As before, the robot shall provide E-Stop and Protective Stop function. Additionally, the robot shall provide in future a Normal Stop function.
The energy supply cut off after stopping shall be provided by a category 0 or 1 stop according to EN 60204-1. The minimum functional safety level of Normal Stop function is foreseen as a PLb according to EN ISO 13849-1.
In practice, the Normal Stop function should be used e.g. for machine stop at end of shift. Such stop should be without creating hazards e.g. without unintended loss of a suspended load. Furthermore, Normal Stop should lessen misuse of Emergency Stop. The publication of the new standard EN ISO 10218-1 is still expected in 2024
