Analog electronic modules
4.3 Basics of Analog Value Processing
ET 200S
Manual, Edition 10/2005, A5E00514527-01
4-17
Non-isolated measuring sensors
The non-isolated measuring sensors are connected to the local ground potential. You must
connect M
ANA
to the ground potential. Depending on local conditions or interference,
potential differences U
CM
(static or dynamic) can occur between the locally distributed
measuring points.
If the permitted value for U
CM
is exceeded, there must be equipotential bonding conductors
between the measuring points.
The following figure illustrates the connection of non-isolated measuring sensors to a floating
analog input module.
Connection of non-isolated measuring sensors to a floating analog input module:
5
4
1
2
3
0
0
/
0
0
$1$
0
0
8
&0
$'8
8
,62
(1)
Logic
(2)
Backplane bus
(3)
Ground bus
(4)
Equipotential bonding cable
(5)
Non-isolated measuring sensors
Operating four-wire measuring transducers on an external voltage supply
If there is isolation between the output and the supply of the measuring transducer, you can
connect it to the 2AI I 4WIRE without additional connections.
If there is no isolation between the output and the supply of the measuring transducer, you
can connect it to the 2AI I 4WIRE only if the reference potential of the power supply voltages
(24 VDC) is the same.
If there is an increase in interference radiation, a connection between M- and M
ANA
on the
terminal module of the 2AI I 4WIRE is recommended.