Siemens SIMATIC ET 200AL System Manual page 33

Connecting
5.3 Electrical configuration of the ET 200AL
Cable protection
According to IEC 60364, cable protection is required, i.e. you must always secure the
incoming lines externally.
You must secure all incoming supply voltages with a UL/IEC approved 24 V DC/4 A fuse
(trigger characteristic type B or C).
Power supply of the configuration
Two voltage groups are available for the distributed I/O system ET 200AL: 1L+ (supply
voltage) and 2L+ (load voltage)
A second infeed may be needed to supply all the modules of a configuration with the
required voltage. Renewed voltage supply of 1L+ and 2L+ can be necessary to configure
different potential groups or because the voltage is not sufficient for all modules due to the
voltage drop. Create a power balance for the selection of the infeed point of the voltage.
Note
Turning 1L+ and 2L+ on and off
In contrast to the load voltage 2L+, the operational switching on and off of the supply voltage
1L+ results in a restart of the module.
The figure below shows a configuration with a new voltage infeed for the modules. The
different potential groups have a gray background.
Figure 5-4
Reference
You will find additional information on electrical configuration and the voltage drop in the
section Connecting cables for ET 200AL (Page 36).
32
Wiring of the power supply
Distributed I/O system
System Manual, 08/2019, A5E31861578-AG