Safety Classification
An international safety standard provides design guidelines for the safety-related parts of control systems in machinery and automated equipment. For system integrators, ISO 13849 establishes the framework used to evaluate the reliability and performance of safety functions. It defines Performance Levels ranging from ‘a’ to ‘e’ to quantify the ability of a control system to perform a safety function under foreseeable conditions.
This standard applies to pneumatic, hydraulic, mechanical and electronic systems, providing a structured approach to machine safety.
Risk Assessment
Hazard identification must be conducted to determine the required safety performance level for each machine function. According to ISO 13849, this involves evaluating the severity of potential injury, the frequency of exposure and the possibility of avoiding the hazard. Designers then select sensors and controllers that match or exceed this calculated level.
The target level ensures the protective circuit is reliable enough.
Diagnostic Coverage
System reliability is calculated by assessing the mean time to dangerous failure of individual components along with their architectural structure. To meet high performance levels under ISO 13849, the system must incorporate automatic self-monitoring and redundancy. This prevents a single component failure from disabling the safety function.
It ensures the machine enters a safe state if an internal fault occurs.
Compliance Validation
Documentation of the safety design must be reviewed and tested before the machine can be deployed in a factory. The validation process ensures that the safety circuits behave exactly as the standard mandates. This certification gives buyers confidence that the system meets global safety benchmarks.
