Siemens SIMATIC ET 200M Operating Instructions Manual page 53

Properties of load power supplies
The load power supply supplies input and output circuits (load circuits) as well as sensors
and actuators. The following lists the properties of load power supplies that are required in
special application cases.
Properties of load power supply
Safer (electrical) isolation
Tolerances of the output
voltage:
20.4 V to 28.8 V
40.8 V to 57.6 V
51 V to 72 V
Rule: ground the load circuits
The load circuits should be grounded.
A perfect functioning security is given on account of the mutual reference potential (ground).
On the load power supply (terminals L or M) or on the isolation transformer provide a
disconnectable connection to the grounding wire (position ④ in the following figure). In the
event of faults in the energy distribution, this measure makes it easier for you to localize
contacts to earth.
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
required for ...
Modules that must be supplied
with voltages ≤ DC 60 V or
≤ AC 25 V
24 V DC load power supply
24 V DC load power supply
48 V DC load power supply
60 V DC load power supply
Assignment planning
3.6 Configuring the electrical structure
Remarks
The power supplies PS 307 as
well as the Siemens load power
supplies of the 6EP1 series
have this property.
In the case of considerable
unevenness of the output
voltage, we recommend using a
supporting capacitor.
Measurement: 200 µF per 1 A
load current (with bridge
rectification).
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