S5-95F Failsafe Mini PLC
S5-95F
Example:
Press control
The protection equipment of a press control must avoid uncontrolled, dangerous
movements.
The undesired event is the uncontrolled starting of the press from standstill or premature stopping
of the press on request. The result of such an event can be major irreversible injury or the death of
the operator (S2).
In this case, we assume that the operator stays frequently to permanently in the hazardous area
(A2). Since press movements are fast processes, the danger can hardly be prevented (G2).
Without protection equipment, the probability of the undesired event arising is relatively high (W3).
According to the risk graph, this results in quality level 5.
Figure 1-3. Press Control
G2
G1
A1
A2
A2
A1
S1
S3
S2
S4
2
3
4
5
6
7
8
W3
1
Quality level
G2
G1
1-4
EWA 4NEB 812 6210-02
