Siemens SIMATIC ET 200SP System Manual page 258

Glossary
Distributed I/O system
System with input and output modules that are configured on a distributed basis, far away
from the CPU controlling them.
DP
Distributed I/O system
→
Earth
Conductive earth whose electrical potential can be set equal to zero at any point.
Equipotential bonding
Electrical connection (potential equalization conductor) that brings the bodies of electrical
equipment and other conductive bodies to the same or almost the same potential, in order to
prevent disruptive or dangerous voltages between these bodies.
Fail-safe modules
ET 200SP modules with integrated safety functions that can be used for safety-related
operation (safety mode).
Fail-safe systems
Fail-safe systems (F-systems) remain in a safe state or immediately assume another safe
state as soon as particular failures occur.
Fault response time
The maximum fault response time of an F-system defines the interval between the
occurrence of any fault and a safe reaction at all affected fail-safe outputs.
For → F-systems overall: The maximum fault response time defines the interval between the
occurrence of any fault at any → F-I/O and the safe reaction at the corresponding fail-safe
output.
For digital inputs: The maximum fault response time defines the interval between the
occurrence of the fault and the safe reaction at the backplane bus.
For digital outputs: The maximum fault response time defines the interval between the
occurrence of the fault and the safe reaction at the digital output.
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Distributed I/O system
System Manual, 12/2015, A5E03576849-AF