Siemens SIMATIC C7-626 Installation, Assembly, Wiring page 89

Isolated The isolated transducers are not connected with the local ground potential.
Transducers
They can be operated free of potential. Local conditions or interference can
cause potential differences V
measuring lines M of the input channels and the reference point of the
measuring circuit M
the permissible value. Where it is possible that the permissible value for V
might be exceeded, or where you cannot determine the difference in potential
accurately, you must connect AIx-M to M
Figure 6-1 shows the principle of connecting isolated transducers to an
isolated analog input module.
Figure 6-1
Non-Isolated
The non-isolated transducers are connected on-site with the ground potential.
Transducers
Depending on local conditions or interference, potential differences (static or
dynamic) can occur between the locally distributed measuring points. To
prevent these potential differences, you must provide equipotential bonding
conductors between the measured value points.
In addition, potential differences V
the measuring lines AIx-M of the input channels and the reference point of
the measuring circuit M
exceed the permitted value. Where it is possible that the permissible value
for V
potential accurately, you must connect AIx-M to M
Figure 6-2 shows the principle of connecting non-isolated transducers to an
isolated analog input module.
C7-626 / C7-626 DP Control Systems
C79000-G7076-C626-01
CM
. However, this potential difference must not exceed
ANA
AIx-X
AIx-M
Isolated
AIx-X
transducers
AIx-M
V
CM
V
Connecting Isolated Transducers to an Isolated Analog Input Module
. However, these potential differences must not
ANA
might be exceeded, or where you cannot determine the difference in
CM
C7 Analog Input/Output
(static or dynamic) to occur between the
.
ANA
ADC
M
ANA
ISO
Ground bus
(static or dynamic) can arise between
CM
.
ANA
CM
Lo
gic C7 CPU
C7
L+
M
6-3
6