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Safety

Safety functions in servo amplifiers

Functional safety

Observing one of the two standards satisfies the supposition of conformity. The functional safety necessary for an installation can be determined either by the Performance Level (PL) according to EN 13849-1, or by establishing a Safety Integrity Level (SIL) according to EN 62061. The standards describe in detail the procedures to analyze an installation's risks.

Comparison SIL - PL

Safety Integrity Level (SIL)
according to EN 62061
Probability of one hazardous
failure per hour (PFH)
Performance Level (PL)
according to EN 13849-1
no specific requirements with respect to safety 10-5 < PFH < 10-4 a
1 (one failure  within 100,000 hrs) 3 x 10-5 < PFH < 10-5 b
1 (one failure within 100,000 hrs) 10-6 < PFH < 3 x 10-6 c
2 (one failure within 1,000,000 hrs) 10-7 < PFH < 10-6 d
3  (one failure within 10,000,000 hrs) 10-8 < PFH < 10-7 e

Risk evaluation

On the basis of the risk analysis, the risk evaluation judges if the risk emerging from goods, services, or from operating an installation is acceptable under the given  basic social conditions, and if  possible residual risks. The evaluations are always carried out before and after the remedies are taken. Thus, in industrial research it is part of extensive risk management, of the systematical application of management policy, of the proceedings and measures to analyze, evaluate, and manage the risk. The risk management is defined by EN 14971.  Nevertheless, legally risk evaluation and risk management are strictly separated from each other.

Relevant standards

  • EN IEC 61508-2 (functional safety of safety-related electrical/electronic/programmable electronic control systems - part 2: demands on safety-related electrical/electronic/ programmable electronic systems)
  • EN IEC 62061 (safety of machinery - functional safety of safety-related electrical/electronic/programmable electronic control systems)
  • EN ISO 13849 (safety-related control components); replaces EN 954-1

BGIA/IFA reports (german)

Further Information