Siemens SIMATIC S7 F, Manual

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Safety
Fail-Safe Systems
7-4
A5E00085588-03
7.2 Safety Requirements
Standardized Safety Requirements
The S7 F/FH System fulfills the following safety requirements:
•
Requirement classes AK1 to AK6 in accordance with DIN V 19250/VDE 0801
•
SIL1 to SIL3 (Safety Integrity Level) in accordance with IEC 61508
•
Categories 1 to 4 in accordance with EN 954-1
Risk Graph and Requirement Classes (AK) to DIN V 19250
Requirement classes (AK) assigned to particular risks are defined in DIN V 19250.
The requirements of the process can be worked out using the risk parameters. The
requirement class (AK) to be complied with by the controller can be established
using the risk chart.
This procedure results in an AK requirement class for applications without a
product standard. Using DIN V VDE 0801, the basic safety requirements can then
be established. If there is a product standard for an application, the safety
requirements are noted in it.
4 3 2
2 1 -
3 2 1
1
W
3
S
1
A
1
A
1
G
1
G
1
A
2
A
2
G
2
G
2
S
2
S
3
S
4
S
1-4
A
1-2
G
1-2
W
1-3
Requirement classes
W
2
W
1
- -
5 4 3
6 5 4
8 7 6
7 6 5
Extent of damage
Length of stay
Avoidance of danger
Probability of undesired
event occurring