Siemens 6ES7134-4FB51-0AB0 - Page 20

Connecting
5.1 Connecting measuring sensors
2AI U HS analog electronic module (6ES7134-4FB51-0AB0)
20 Manual, 04/2007, A5E01076015-01
Abbreviations used
The meanings of the abbreviations in the figures below are as follows:
M + Measuring line (positive)
M - Measuring line (negative)
M
ANA
Analog measuring circuit reference potential
M Frame connection
L + Rated load voltage 24 VDC
U
CM
Potential difference between inputs and reference potential of the measuring
circuit M
ANA
U
ISO
Potential difference between M
ANA
and central grounding point
Isolated measuring sensors
The isolated measuring sensors are not connected to the local ground potential. They can be
floating. Depending on local conditions or interference, potential differences U
CM
(static or
dynamic) can occur between the measuring lines M- of the input channels and the reference
point of the measuring circuit M
ANA
.
To ensure that the permitted value for U
CM
is not exceeded in environments with strong EMC
interference, the following applies:
● For the 2 AI U analog input module: Connect M- with M
ANA
!
The following figure illustrates the connection of isolated measuring sensors to the floating
analog input modules.
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0
0
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9
9
1
2
3
4
5
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0
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8
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8
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① Logic
② Backplane bus
③ Ground bus
④ Central grounding point
⑤ Isolated measuring sensors