Siemens simatic ET 200MP, System Manual

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Application planning
4.3 Setting up power segments
ET 200MP Distributed I/O System
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System Manual, 01/2013, A5E03723484-01
4.3 Setting up power segments
Definition
A power segment comprises a group of modules, whose supply voltage is made available
via the backplane bus by the interface module and/or a power supply module.
On setting up power segments
The IM 155-5 PN ST interface module always constitutes the first power segment. It has an
integrated power supply, that feeds 14 W into the backplane bus (if the interface module is
supplied on the front side with 24 V DC). By inserting a power supply (PS) module before the
interface module, the power of the first power segment can be increased by the power of the
power supply module (thus 14 W + 25 W or 14 W + 60 W).
If the configuration requires more power, then insert for example an additional power supply
module after the last I/O module of the first power segment; this power supply will supply the
subsequent I/O modules with voltage. (See the sample calculation in the chapter Power
budget calculation (Page 32).)
In this alternative configuration, the (power supply ) interface module and the
additional power supply module each span their own power segment. The interface module
additionally controls the internal communication bus for all modules of the ET 200MP;
however the supply voltage of the station is divided into 2 power segments.
Response to failure of power supplies
If the power supply of a power segment fails or is switched off, all I/O modules to the right of
the affected power supply are no longer detected. This is also true for I/O modules in a
supplied power segment that is to the right of a power segment that is deactivated or not
supplied.