Technical details
Operating Manual PIT m4SEU
1004648-EN-02
| 65
Safety-related architecture
SRP/CS
SRP/CS
SRP/CS
Input
Logic
Logic
Pushbutton
PIT m4SEU
n/o
Input
+
diagnostics
MSO (mode of
safe operation)
Safety controller
INFORMATION
In accordance with EN ISO 13849-1, the following parameters may be ap-
plied for the external pushbuttons with N/O contact:
}
For the "operating mode selection" safety function it is sufficient for a safety level to be
calculated for just one pushbutton.
}
Cat. 2 can be estimated for the subsystem pushbutton; the following conditions are met:
– Demand rate = Test rate (1 to 1) – Testing occurs immediately upon demand of the
safety function and the overall time to detect the fault and to bring the machine to a
non-hazardous condition is shorter than the time to reach the hazard.
– MTTF
D
,TE (Test equipment) > 0.5*MTTF
D
,L (Logic)
}
DC 90 % (shorts between contacts in the wiring are also detected)
}
Measures against CCF (min. score of 65 in accordance with Table F.1 (EN ISO 13849-1)
can be considered to have been fulfilled if the user can confirm that the items marked
"Customer" have been fulfilled (see table below).
