Glossary
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05
Glossary-9
F-User Blocks
S7 F/FH Systems: Block container of
Failsafe Blocks library containing the -> F-blocks that
the user can position, assign parameters to, and interconnect in -> continuous function
charts (CFC).
Light Period
Light periods occur during complete bit pattern tests. Test-related "1" signals are switched
from the fail-safe output module to the output bit while the output is deactivated (output
signal "0"). The output is then switched on briefly (light period). A sufficiently slow actuator
does not respond to this and remains switched off.
Master-Reserve Switchover
In S7 FH Systems, a master-reserve switchover is triggered when the master goes to STOP
mode. That is, the system switches from the master CPU to the reserve CPU.
MSR
Instrumentation and control technology
Non-equivalent Sensor
A non-equivalent -> sensor is a reversing switch that is connected (via two channels) to two
inputs of an -> F-I/O in -> fail-safe systems (for -> 1oo2 evaluation of sensor signals).
OBT
Optical Bus Terminal (OBT): Equipment used to connect an individual PROFIBUS DP device
without an integrated optical interface or an RS 485 segment to the optical PROFIBUS DP.
OLM
Optical Link Module (OLM): Equipment used for fiber-optic interfacing to convert electrical
signals into optical signals and vice versa.
OP
Operator Panel (OP): A programmable HMI device used to operate and monitor machines
and systems.
OS
Operator Station (OS): A configurable operator station used to operate and monitor
machines and systems.
