CH 6 - Selection of an interlocking device

When selecting an interlocking device for a machine, it is necessary to consider all phases of the machine life cycle.

Some provided selection criteria are:

• The conditions of use and intended use of the machine;
• The hazards present at the machine;
• The severity of the possible injury;
• The probability of failure of the interlocking device;
• Overall system stopping performance and access time;
• The required PL or SIL for the safety function;
• Information for use provide for the interlocking device;
• For type 4 interlocking devices the means to avoid that a single actuator can be taught in an unlimited manner by the operator without special knowledge and tools.