Connecting Non-Floating Or Floating Modules - Siemens S5-135U/155U System Manual

Installation Guidelines
3.4.3

Connecting Non-Floating or Floating Modules

Shown in the following sections are the specical features when installing
non-floating and floating modules.
Installation with
In an installation with non-floating modules, the reference potentials of the
Non-Floating
control circuit (0 V
Modules
The reference potential of the control circuit (0 V
protective conductor terminal and must be connected to the reference
potential of the load circuit via an externally laid conductor.
Shown in the following figure is a simplified installation with non-floating
modules. The arrangement is independent of the grounding concept. The
connections for grounding are therefore not drawn.
PS
1L+
1L–
PE
Control Power External Connection for a
Supply Standard Reference Potential
2L+
2L–
DC 24 V Load Power Supply
Figure 3-11 Simplified Representation of an Installation with Non-Floating Modules
The voltage drop on line
shift in reference potentials resulting in module malfunctions.
3-26
) and load circuits (0 V
int
CPU
DI
must not exceed 1 V. Otherwise there will be a
) are electrically connected.
ext
) is given by the PE or
int
U
int
Data
0 V
DQ
System Manual
C79000-G8576-C199-06