Siemens SIMATIC ET 200M Operating Instructions Manual page 50

Assignment planning
3.6 Configuring the electrical structure
Supply voltage
The following table identifies requirements to be observed for the line voltage.
With ...
Stationary plants or systems without all-
pole line voltage disconnect switch
Load power supplies, power supply
modules
All ET 200M circuits
24 V DC supply
The following table identifies requirements to be observed for the 24 V supply.
With ...
Buildings
24 V DC supply lines, signal
lines
24 V DC supply
Protection against outside electrical influences
The following table identifies requirements you must observe to provide protection against
electrical influences or faults.
With ...
All plants or systems in which the
ET 200M is integrated
Connection, signal and bus lines
Signal and bus lines
48
the ...
There must be a supply isolating switch or a fuse in the
building installation system
The system voltage range set must correspond to the
local system voltage
fluctuation / deviation of the input / load voltage from the
rated value must lie within the permissible tolerances
(refer to Technical Specifications of the S7-300 modules)
you must ensure ...
Outdoor lightning protection
Indoor lightning protection
Safe electrical isolation of safety extra-low voltage
you must ensure ...
that the unit or the system is connected to the grounding wire in
order to discharge 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.
Operating Instructions, 12/2008, EWA-4NEB780600602-08
to provide lightening protection
measures
(e.g. lightening protection ductors)
ET 200M