Siemens Simatic M7-400 Reference Manual page 275

5.13 Connecting Loads/Actuators to Analog Outputs
Introduction
You can use the analog output modules to supply loads and actuators with current
and voltage.
This section contains general information that is generally applicable to all the
connection options for loads and actuators described in the sections that follow.
Cables for Analog Signals
For the analog signals
Q and S+ and M and S–, respectively, are to be twisted together. This reduces the
V
interference
If there are potential differences between the cable ends, an equipotential
bonding current, which can flow over the shield, can cause interference of the
analog signals. In such a case, you should ground the shield at one end of the
cable only.
Isolated Analog Output Modules
With the isolated analog output modules there is no electrical connection between
the reference point of the measuring circuit M
You must use isolated analog output modules if a potential difference U
occur between the reference point of the measuring circuit M
ground. By means of an equipotential bonding conductor between the M
terminal and chassis ground, make sure that U
value.
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
you should use shielded and twisted pair cables. The cables
,
Ground the screen of the analog cables at both ends of the cables.
.
Analog Modules
and chassis ground.
ANA
and chassis
ANA
does not exceed the permitted
ISO
can
ISO
ANA
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