Configuring
4.9 Electrical assembly, protective measures and grounding
S7-300, CPU 31xC and CPU 31x: Installation
4-16 Operating Instructions, Edition 08/2004, A5E00105492-05
Specified components and protective measures
A number of components and protective measures are prescribed for plant installations. The
type of components and the degree of compulsion pertaining to the protective measures will
depend on the VDE specification applicable to your particular plant.
The table below shows components and protective measures.
Table 4-7 VDE specifications for the installation of a PLC system
Compare ... 1) VDE 0100 VDE 0113
Disconnect devices for control
systems, signal generators and
final control elements
(1) ...Part 460:
Master switch
... Part 1:
Load disconnect switch
Short-circuit / overload
protection:
In groups for signal generators
and final control elements
(2) ...Part 725:
Single-pole fusing of
circuits
... Part 1:
• With grounded secondary
power circuit: single-pole
fusing
• Otherwise: fusing of all poles
Load power supply for AC load
circuits with more than five
electromagnetic devices
(3) Galvanic isolation by
transformer
recommended
Electrical isolation by transformer
mandatory
1) This column refers to the indexes of the figure in the chapter Overview: Grounding.
Reference
For further information on protective measures, refer to the Appendix.
4.9.2 Installing an S7-300 with grounded reference potential
Introduction
During installation of an S7-300 with grounded reference potential interference current is
discharged to the ground conductor / to earth. A grounding slide contact is used for this
except with CPU 31xC.
Note
Your CPU is supplied with grounded reference potential. Therefore, if you wish to install an
S7-300 with grounded reference potential, you do not need to modify your CPU!
To Next Page
Loading...
