500 and 800 Series Encoders

The issue of human safety according to the Machinery Directive 2006/42/EC is becoming more important as the global economy drives us toward common standards. As part of the worldwide Functional Safety initiatives for machinery, LEINE & LINDE is supporting design engineers with reliability data for their 500 and 800 series encoders, available from Heidenhain, in support of this directive.

Common machinery functional safety applications are seen in industries such as oil & gas, process control, railways, mining, power generation, cranes, machine tools, etc.

To demonstrate adequate consideration of human safety concepts in machine design, engineers must be able to calculate either the performance level, PL, according to EN ISO 13849-1 or the PFHd value for the Safety Integrity Level, SIL according to IEC 61508.

To calculate the Performance Level, values for the Mean Time To (dangerous) Failure are needed for any single component of the safety system. Using the guidelines of 13489-1 supported by failure mode effects diagnostic analysis (FMEDA) or similar methodologies, the designer can determine the MTTFd value for the Functional Safety System.

The calculation of the SIL level for continuous operation of equipment is based upon the Probability of (dangerous) Failures per Hour, of PFHd.

To support these analyses, both PFHd and MTTFd values are now available when LEINE & LINDE 500 and 800 series encoders are used as the input components.