In 1995 CEN published an important standard for machine builders – EN 954 – 1, Safety of Machinery – Safety Related Parts of Control Systems – Part 1: General Principles for Design. This standard set the stage for defining control reliability in machinery safeguarding systems, introducing the Reliability categories that have become ubiquitous. So what do these categories mean, and how are they applied under the latest machinery standard, ISO 13849 – 1?
Did you know that interlocked gates require stopping performance testing?
Machinery needs to be able to stop in the time it takes a person to open the guard and reach the hazard. If the distance from the guard opening to the hazard is short enough that a person can reach the danger point before the hazard can be controlled, the guard is useless. The resulting situation may be worse
I get a lot of calls and emails asking about emergency stops. This is one of those deceptively simple concepts that has managed to get very complicated over time. Not every machine needs or can benefit from an emergency stop. In some cases, it may lead to an unreasonable expectation of safety from the user, which can lead to injury if they don’t understand the hazards involved. Some product-specific standards