Siemens Simantic ET200SP - Page 304

Glossary
Distributed I/O system
304 System Manual, 12/2016, A5E03576849-AG
Safety class
Safety level (Safety Integrity Level) SIL according to IEC 61508:2010. The higher the Safety
Integrity Level, the more rigid the measures for prevention of systematic faults and for
management of systematic faults and hardware failures.
The fail-safe modules support operation in safety mode up to safety class SIL3.
Safety frame
In safety mode, data are transferred between the → F-CPU and → F-I/O in a safety frame.
Safety function
A mechanism integrated in the → F-CPU and → F-I/O that enables their use in → the fail-safe
system SIMATIC Safety.
According to IEC 61508:2010: A safety function is implemented by a safety system in order
to maintain or force a system safe state in the event of a specific fault.
Safety mode
Operating mode of → F-I/O that enables → safety-related communication via → safety frames.
→ ET 200SP fail-safe modules can only used in safety mode.
Safety program
Safety-related user program
Safety-related communication
Communication used to exchange fail-safe data.
Self-assembling voltage buses
Two internal, self-assembling buses (P1 and P2) that supply the I/O modules with voltage.
SELV
S
afety
E
xtra
L
ow
V
oltage
Sensor evaluation
There are two types of sensor evaluation:
→ 1oo1 evaluation – sensor signal is read once
→ 1oo2 evaluation – sensor signal is read in twice by the same F-module and compared
internally