Operation Of The Cm On Grounded/Ungrounded Power Supply - Siemens SIMATIC RF166C Operating Instructions Manual

5.2

Operation of the CM on grounded/ungrounded power supply

Below, you can find information on the overall configuration of an RF166C communication
module on a grounded power supply (TN-S network). The specific subjects discussed here
are:
• Supply voltages of the communications module
• Disconnecting devices, short-circuit and overload protection according to IEC 60364
(corresponds to DIN VDE 0100) and IEC 60204 (corresponds to DIN VDE 0113)
• Load voltage supplies and load circuits
Grounded power supply
For grounded power supplies, the neutral conductor of the supply system is grounded. A
short-circuit to ground of a live conductor, or of a grounded part of the system, trips the
protective devices.
Supply voltages
Two supply voltages are available for the communications module:
• 1L+: Power supply
• 2L+: Load voltage
Note that the power supply (1L+) supplies the communications module and the readers with
power. Load voltage (2L+) has no direct effect on the communications module. This voltage
is looped through to further consumers via the L-coded plug-in connectors.
Safe electrical isolation (SELV/PELV according to IEC 61140)
Power supply units/power supply modules with safe electrical isolation are required for
operation of the communications module. This protection is referred to as SELV (Safety Extra
Low Voltage) / PELV (Protective Extra Low Voltage) according to IEC 61140.
Configuring RF166C with grounded reference potential
When the communications module is set up with grounded reference potential, any
interference currents that occur are diverted to functional ground. The connections must be
connected externally (connection between 1M and FE).
Configuring RF166C with ungrounded reference potential
When the communications module is set up with ungrounded reference potential, any
interference currents occurring are conducted to functional ground via an internal RC
network (no external connection between 1M and FE).
SIMATIC RF166C
Operating Instructions, 03/2022, C79000-G8976-C578-02
5.2 Operation of the CM on grounded/ungrounded power supply
Connecting
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