Analog Modules
4-47
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
You can operate the CPU in Grounded mode (refer to the figure below) or
Ungrounded mode.
Isolated
sensors
M+
M
L+
M–
M
ANA
M+
M–
Backplane
bus
ADC
M
internal
L+
M
Ground bus
CPU
U
ISO
Recommended
connection
Logic
Figure 4-7 Connecting Isolated Sensors to an Isolated AI
Isolated
sensors
M+
M
L+
M–
M
ANA
M+
M–
Backplane
bus
M
internal
L+
M
Ground bus
CPU
ADC
Recommended
connection
Logic
Figure 4-8 Connecting Isolated Sensors to a Non-Isolated AI
Note
Do not connect M– to M
ANA
when connecting 2-wire transmitters for current
measurement and resistance-type sensors. This also applies to inputs which are
not used.