Overview: Grounding - Siemens S7-300 Installation Manual

Configuring

5.8.5 Overview: Grounding

CPU 312 IFM
The figure below shows you the complete assembly of an S7-300 with CPU 312
IFM with a power supply from TN-S power supply. Apart from powering the CPU,
the PS 307 also supplies the load current for the 24 VDC modules. Note: The
arrangement displayed does not correspond with the physical arrangement; it was
merely selected to give you a clear overview.
L1
L2
L3
N
PE
1
Figure 5-11 Grounding concept for the S7-300 with CPU 312 IFM
Table 5-10
The main switch
(1)
Short-circuit/overload protection
(2)
The load current supply (galvanic isolation)
(3)
This connection is established automatically with the CPU 312 IFM.
(4)
5-28
Rail
L1
N
3
AC
AC
AC
DC
AC
DC
Connection of the load voltage reference potential
The diagram illustrates under number
S7-300 Automation System, Hardware and Installation: CPU 312IFM - 318-2 DP
Low-voltage distribution
e. g. TN-S system (3 x 400 V)
Cabinet
CPU
PS
4
1
µP
L +
M
Signal modules
Ground bus in cabinet
2
AC 24 to 230 V load circuit for
AC modules
2
DC 5 to 60 V load circuit for
non-isolated DC modules
2
DC 5 to 60 V load circuit for
isolated DC modules
SM
A5E00203919-01