Siemens SINAMICS G120 Function Manual page 223

As part of the iterative process to achieve the required level of safety, a risk assessment is
carried out after the risk estimation. A decision must be made here as to whether the
residual risk needs to be reduced. If the risk is to be further reduced, suitable protective
measures must be selected and applied. The risk assessment must then be repeated.
Figure A-2
Risks must be reduced by designing and implementing the machine accordingly (e.g. by
means of controllers or protective measures suitable for the safety-related functions).
If the protective measures involve the use of interlocking or control functions, these must be
designed in accordance with EN ISO 13849-1. For electrical and electronic controls, EN
62061 can be used as an alternative to EN ISO 13849-1. Electronic controls and bus
systems must also comply with IEC/EN 61508.
Safety Integrated Function Manual, SINAMICS G120 and G120C
Function Manual, 01/2011, FW 4.4, A5E03052391B AB
Iterative process to achieve the required level of safety to ISO 14121-1
A.1 Standards and specifications
Appendix
221