Table of Contents
Advertisement
Installation Guidelines
Operating a programmable controller with field devices on a centrally grounded supply
In plants with their own transformers or generators, the PLC is connected to the central
grounding point. A removable connection must be provided for measuring ground faults.
Installation of the PLC must be such that there is insulation between the cabinet potential and the
protective conductor potential. In order to maintain the insulation, all connected devices must be
grounded capacitively or they must be nongrounded . For this reason, programmers must be
supplied only via an isolating transformer.
Low voltage distribution
L1
L2
L3
Removable connection
for measuring purposes
Central operating
ground or
fundamental ground
Control power supply
AC
DC
AC
AC
AC
DC
AC
DC
N
Figure 3-31.
Operating a Programmable Controller with Field Devices on Centrally
Grounded Supply
3-38
Cabinet
L+
L+/L1
L-
U int
L-/N
L1
PS
M int
N
PE
Protective conductor bar in
cabinet, insulated
24 to 230 V AC load power supply unit for
AC modules
5 to 60 V DC load power supply unit for
nonfloating DC modules
5 to 60 V DC load power supply unit for
floating DC modules
Programmable controller with insulated installation
µ
P
Non-
Non-
CPU
floating
floating
input
output
Field devices
EWA 4NEB 811 6130-02b
S5-115U Manual
Floating
Floating
input
output
Advertisement
Table of Contents
