Glossary
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05
Glossary-13
Safety Message Frame
In -> safety mode, data are transferred in a safety message frame
between the -> F-CPU and the -> F-I/O or, in safety-related CPU-to-CPU communication,
between the F-CPUs.
Safety Mode
1. Safety mode is the operating mode of the -> F-I/O that allows -> safety-related
communication using -> safety message frames. -> Fail-safe modules ET 200S, ET
200pro und ET 200eco are designed for safety mode only. -> F-SMs S7-300 can be used
in -> standard mode or safety mode (except SM 326; DO 8 × DC 24V/2A).
2. Operating mode of the -> safety program. In safety mode of the safety program, all safety
mechanisms for fault detection and fault reaction are activated. In safety mode, the safety
program cannot be modified during operation. Safety mode can be deactivated by the
user (-> deactivated safety mode).
Safety Program
The safety program is a safety-related user program.
Safety Protector
The safety protector protects the -> F-SMs from possible overvoltages in the event of a fault.
The safety protector must be used for SIL3/Cat.4 applications:
•
Generally, when PROFIBUS DP is configured with copper cable
•
When PROFIBUS DP is configured with fiber-optic cable and combined operation of
standard signal modules and -> F-SMs in one ET 200M is required
Safety-related Communication
Safety-related communication is communication used to exchange fail-safe data.
Sensor Evaluation
There are two types of sensor evaluation:
•
-> 1oo1 evaluation – Sensor signal is read out once
•
-> 1oo2 evaluation – The sensor signal is read twice by the same -> F I/O and compared
internally.
Sensors
Sensors are used for exact measurement of paths, positions, velocities, rotational speeds,
masses, etc.
