Siemens Simatic S7-400 - Manual (Page 278)

Analog Modules
5-62
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
5.15 Connecting Loads/Actuators to Current Outputs
Note
The necessary connecting cables, which result from the potential connection of the
analog output module, are not drawn in the figures shown below.
In other words, you must continue to take note of and implement Section 5.13 with
its generally applicable information for connecting loads/actuators.
Abbreviations and Mnemonics Used in the Figure Below
The abbreviations and mnemonics used in the figure below have the following
meanings:
Q
I
: Analog output current
M
ANA
: Reference potential of analog circuit
R
L
: Load impedance
L +: Terminal for 24 VDC supply voltage
M : Ground terminal
U
ISO
: Potential difference between M
ANA
and chassis ground
Connecting Loads to a Current Output
You must connect loads to Q
I
and the reference point of the analog circuit M
ANA
of
a current output.
+24 V
R
L
L
+
QI
M
ANA
M
0 V
U
ISO
Chassis ground
Figure 5-23 Connecting Loads to a Current Output of an Isolated AO