Siemens SIMATIC ET 200AL, System Manual

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Distributed I/O system
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System Manual, 08/2021, A5E31861578-AJ
Glossary
1oo1 evaluation
Type of → sensor evaluation – in the case of the 1oo1 evaluation, there → is one sensor with
a 1-channel connection to the F module.
1oo2 evaluation
Type of → sensor evaluation – in the case of 1oo2 evaluation , two input channels are
assigned one two-channel sensor or two one-channel sensors. The input signals are
compared internally for equivalence or nonequivalence.
Access protection
Fail-safe systems must be protected against dangerous, unauthorized access. Access
protection for F-systems is achieved by assigning two passwords (for the
fail-safe CPU and the safety program).
Acknowledgment time
During the acknowledgment time, the → F-I/O acknowledge the sign of life specified by the
→ F-CPU. The acknowledgment time is included in the calculation of the → monitoring time
and → response time of the overall fail-safe system.
Actuator
Actuators are, for example, power relays or contactors for switching on load devices or load
devices themselves (e.g. directly controlled solenoid valves).
Availability
Availability is the probability that a system is functional at a specific point in time. Availability
can be increased by redundancy, e.g., by using multiple -> sensors at the same measuring
point.
Bus
A common transfer route to which all devices are connected; it has two defined ends.