Parallel Connection For Redundancy - Siemens LOGO!Power Series Operating Instructions Manual

9.2

Parallel connection for redundancy

The parallel switching of several LOGO!Power power supplies of the same type for
redundancy is required when the demands for reliability of the supply are particularly high.
If a component in the redundant supply fails, the power supply for the loads must be fully
accommodated by the remaining component. It is therefore important when dimensioning the
system to make sure that n+1 redundant switched power supplies can handle the total power
requirement of the remaining n power supplies.
To prevent loading of the remaining power supplies in the event of a secondary-side error
when one power supply fails, the respective "+" terminals of the power supplies must be
decoupled via diodes.
Note
For a high reliability of the supply, it is recommended that the redundant switched power
supplies are fused separately on the line-side and, if possible, be connected to different
power supply networks.
Figure 9-2
LOGO!Power
Operating Instructions, 06.2014, C98130-A7560-A999-3-7629
Parallel connection for redundancy
9.2 Parallel connection for redundancy
Applications
49