S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
A-1
Appendix
A
A.1
General rules and regulations for S7-300 operation
Introduction
Seeing that an S7-300 can be used in many different ways, we can only describe the basic
rules for the electrical installation in this document.
Warning
Always observe these basic rules for electrical installation in order to achieve a fully
functional S7-300 system.
EMERGENCY-OFF equipment
EMERGENCY-OFF equipment to IEC 204 (corresponds to VDE 113) must remain effective
in all operating modes of the plant or system.
System startup after specific events
The table below shows what you have to observe when restarting a plant after specific
events.
Table A-1
System startup after specific events
If there is...
then ...
Restart following a voltage dip or power failure,
dangerous operating states must be excluded. If
necessary, force EMERGENCY-OFF.
Startup after releasing the EMERGENCY OFF
device,
uncontrolled or undefined startup operations must
be excluded.