Siemens SIMATIC S7 F Manual page 348

Glossary
1oo1 evaluation
R
Redundancy, Availability-
Enhancing
Redundancy, Safety-
Enhancing
S
Safety Program
Safe state
Safety
Safety frame
Safety function
Safety integrity level
Safety mode
Safety note
Glossary-4
Type of sensor evaluation: In 1oo1 evaluation, there is one sensor and it
is connected to the module via a single channel.
Multiple availability of components with the aim of ensuring the
components continue to function even in the event of hardware faults.
Multiple availability of components with the aim of compensating for
revealing hardware faults through comparison (e.g. 1oo2 evaluation in S7
F/FH Systems).
Fail-safe user program or F Program consisting of the fail-safe blocks of
the "Failsafe Blocks" library.
State of a unit in which safety is assured. In other words, the risk is
acceptably low because it has been established that safety-related
malfunctions do not occur or because of the safety measures taken to
prevent possible safety-related malfunctions.
Safety is a state in which the risk is not higher than the acceptable risk.
In safety mode, data is transferred in a safety frame between the CPUs
or between the CPU and the fail-safe signal modules.
In accordance with IEC 61508: A function implemented by a safety
system to ensure that the system is kept in a safe state or brought into a
safe state in the event of a problem.
All of the hardware and software components that are involved in
implementing a certain process subfunction.
Safety level between 4 and 1 in accordance with IEC 61508 and prEN
50129. The higher the safety integrity level, the more comprehensive are
the measures to avoid systematic errors and control systematic errors
and hardware failures.
Safety mode of the fail-safe signal modules
Operating mode of the fail-safe signal modules used in S7 F/FH
Systems. In safety mode, access to the inputs and outputs of the fail-safe
signal modules is only permitted via the fail-safe driver blocks of the
"Failsafe Blocks" library.
Safety mode of the safety program
Operating mode of the safety program in S7 F/FH Systems. All the safety
mechanisms for fault detection and fault responses are activated in
safety mode of the safety program. It is not possible to change the safety
program during operation when it is in safety mode.
Important information relating to the acceptance and safety-related use of
the product.
Fail-Safe Systems
A5E00085588-03