Siemens S5-135U/155U System Manual page 400

Analog Input/Output Modules
Example:
(Special case) The temperature of the busbar of an electroplating bath is to be
measured with an uninsulated thermocouple.
Sensor,
Not Isolated
+
U E
–
+
U CM
–
Figure 9-7 Measuring Circuit without Equipotential Bonding Conductor for the 460 Analog Input Module
The potential of the busbar with respect to the reference potential of the
module is, for example, 24 V DC. A 460 analog input module with isolated
input is used (U
conductor must not be laid here because it would short-circuit the busbar.
9-18
Analog Input Module
M+
M–
Range
Card for
4 Inputs
U CM
= 60 V AC/75 V DC). An equipotential bonding
CM
A
MUX
#
D
0 V Bus
C79000-G8576-C199-06
System Manual