Siemens SIMATIC ET 200M Manual page 91

Wiring
Protection From External Electrical Exposure
The following table shows you what to remember about protection from electrical
exposure and faults.
With ...
All plants or systems in
which the ET 200M is
integrated
Connection, signal and
bus lines
Signal and bus lines
Rules on the Power Consumption and Power Loss of an ET 200M
The S7-300 modules get the power they need for operation from the backplane
bus and, if necessary, from an external load power supply.
S The power consumption of all the signal modules from the backplane bus must
not exceed the power the IM 153-x can deliver to the backplane bus.
S The PS 307 power supply is dependent on the power consumption from the
24V load power supply; this is made up of the total power consumption of the
signal modules and all other connected loads.
S The power loss of all the components in a cabinet must not exceed the
maximum thermal rating of the cabinet.
Tip: When establishing the required dimensions of the cabinet, ensure that the
temperature inside the cabinet does not exceed the permissible 60 _C even
where external temperatures are high.
You will find the values for the power consumption and power loss of a module
under the technical specifications of the relevant modules.
5-4
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Make Sure That ...
... the plant or system is connected to the protective
conductor for diverting electromagnetic interference.
... the wiring routing and installation are correct.
... any break of a line or conductor does not result
in undefined states of the plant or system.
Distributed I/O Device ET 200M
EWA-4NEB780600602-06