Connection
5.3 Electrical design of the CM
SIMATIC RF185C, RF186C, RF188C, RF186CI, RF188CI
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Operating Instructions, 04/2020, C79000-G8976-C512-03
Circuit breaker
According to IEC 60364, line protection is required, i.e. the supply lines must always be
protected externally.
All supply voltages must be protected with a UL/IEC approved fuse 24 V DC / 16 A (tripping
characteristic type B or C). At ambient temperatures of 40 °C to 55 °C, the power supplies
must be protected with a UL/IEC approved fuse 24 V DC / 12 A.
Power supply of the assembly
Two voltage groups are available for the communication module, 1L+ (supply voltage) and
2L+ (load voltage).
Another power supply may be required in order to supply all communication modules of an
assembly with the required voltage. Another voltage supply of 1L+ and 2L+ may be needed
to form different potential groups, or because the voltage is insufficient for all communication
modules due to the voltage drop. Create a power budget for the selection of the supply point
of the voltage.
Note
Switching 1L+ and 2L+ on and off
Note that the power supply (1L+) supplies the communication module and the readers with
power. The load voltage (2L+) has no direct effect on the RF18xC communication modules.
For RF18xCI, the actuators and connected IO-Link devices (connectors with Class B
assignment) are supplied with power over the load voltage (2L+). If the load voltage (2L+) is
not connected, the channel fault LED (IO-L1) is continuously lit in red. This voltage is looped
through to further consumers via the I/O interface.
