Phoenix Contact 2702924, Руководство пользователя

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Application manual for PSRclassic and PSRmultifunction, and the modular safety relay system
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PHOENIX CONTACT 102597_en_03
2.3.4 Dividing the safety function into subsystems
Following technical implementation and identification of safety-related components, a
safety-related block diagram must be created for further evaluation. As a rule, a safety func-
tion consists of sensor - logic - actuator. In the simplest case, each one is a subsystem.
These subsystems are connected in series to form the overall safety function (see “Safety-
related block diagram (in accordance with EN 13849-1)” on page 12 ).
Determination of the safety integrity for each subsystem
A characteristic value when determining the safety integrity level (SIL) is the PFH
D
value,
the statistical “average frequency of a dangerous failure per hour”.
The safety characteristics for Phoenix Contact products can be found in the
DB EN SAFETY CHARACTERISTICS data sheet or the SISTEMA library.
Standard EN 62061 describes the subsystem architectures type A to D, which are similar to
the categories of EN ISO 13849-1.
Figure 2-6 Logical representation of subsystem A (in accordance with EN 62061)
Figure 2-7 Logical representation of subsystem B (in accordance with EN 62061)
λ
Den
λ
De1
Subsystem A
Subsystem
Element n
Subsystem
Element 1
λ
De1
λ
De1
λ
De1
λ
De2
Subsystem B
Subsystem
Element 1
Subsystem
Element 2
Common
cause
failure