Risk Assessment - Siemens SIMATIC HMI Mobile Panel 277 RO Operating Instructions Manual

2.6

Risk assessment

Performing risk assessment
The following standards must be used to perform the risk assessment:
● EN ISO 12100:2010, General principles for design of machinery
● ISO 14121-1:2007, Risk Assessment for Machinery
● EN ISO 13849-1:2008/AC:2009, Safety-related parts of control systems
These considerations result in a performance level (PL a to e) in accordance with
EN ISO 13849-1:2008/AC:2009 which ultimately dictates how the safety-related parts of the
system to be monitored must be procured.
For evaluations of safety functions according to IEC EN 62061, the specified performance
level (PL) can be converted to SIL according to the EN ISO 13849-1 equivalence table:
Performance Level
Note: Aside from the average probability of one hazardous failure per hour, additional measures are
necessary to achieve the PL.
The connection examples with various monitoring devices in the section "Wiring Examples
for Enabling Switch and STOP Button (Page 142)" show how the safety-related parts of the
mobile panel can achieve Category 3 PL d in accordance with
EN ISO 13849-1:2008/AC:2009. Attention must be paid that the overall concept of the
system is designed with this in mind.
Mobile Panel 277 RO
Operating Instructions, 10/2015, A5E36824256-AA
Safety Integrity Level (SIL)
(PL)
(IEC 61508-1, for information
High/continuous operating mode
a
b
c
d
e
purposes only)
No equivalent
1
1
2
3
Safety instructions and general notes
2.6 Risk assessment
Average probability
of one hazardous failure per hour
1/h
≥ 10 to < 10
-5
≥ 3 x 10 to < 10
-6
≥ 10 to < 3 x 10
-6
≥ 10 to < 10
-7
≥ 10 to < 10
-8
-4
-5
-6
-6
-7
25