Siemens RUGGEDCOM RM1224, Operating Instructions Manual

Page: 29 / 54

Connecting up
3.4 Grounding
RUGGEDCOM RM1224
Operating Instructions, 10/2016, RC1260-EN-02
29
External power supply
Note
Permitted external power supplies
The power supply unit to supply the RUGGEDCOM RM1224 must comply with the
requirements for a limited power source according to IEC/EN 60950-1, section 2.5.
The external power supply for the RUGGEDCOM RM1224 must meet the requirements for
NEC class 2 circuits as specified in the National Electrical Code ® (ANSI/NFPA 70).
Refer to the section Connecting up (Page 25) and the installation instructions and
instructions for use of the manufacturer of the power supply, the battery or the accumulator.
Note
External power supply for operation in China
The device may only be used with an external power supply that has a CCC approval.
3.4 Grounding
EMC disturbances are diverted to ground via ground. This increases the immunity of the
data transmission.
It is crucial for the correct operation of ground that the connection to the reference potential
surface always has low impedance. Such a connection of the functional ground of the device
does not go first through the cable channel and then to the mounting plate or DIN rail
terminal, but goes directly to the mounting plate or DIN rail terminal.
The RUGGEDCOM RM1224 has a terminal for grounding, refer to the section "Power supply
(Page 28)".
The terminal is identified by the following symbol for the grounding.
1. Connect the terminal of the device with as short a cable as possible ≤ 150 mm and a
large cross-sectional area ≥ 2.5 mm² to the functional ground of the system. In many
cases, the entire metallic construction of the system serves as ground.
2. Also connect the standard rails of a system with ground.
Protective earth/functional ground
The connection of the reference potential surface with the protective earth system is
normally in the cabinet close to the power feed-in. This earth conducts fault currents to
ground safely and according to DIN/VDE 0100 is a protective earth to protect people,
animals and property from too high contact voltages.
Apart from the protective earth, there is functional grounding in the cabinet. According to
EN60204-1 (DIN/VDE 0113 T1) electrical circuits must be grounded. The chassis (0 V) is