Grounding; Twisted Pair Cable - Siemens CSM 1277 Operating Instructions Manual

NOTICE
The previous device CSM 1277 with order number 6GK7277-1AA00-0AA0 had a different
pin assignment of the terminal block. Pin 1: Functional grounding, Pin 2: Protective earth,
Pin 3: L+.
The supply input of the CSM is protected against polarity reversal. A reverse polarity of the
supply voltage does not cause any damage but will not result in any function either.
The device is designed for operation with safety extra-low voltage. This means that only
safety extra-low voltages (SELV) complying with IEC 60950-1/EN60950/VDE0805 can be
connected to the power supply terminals.
The power supply unit for the device power supply must meet NEC Class 2, as described
by the National Electrical Code(r) (ANSI/NFPA 70).
The power of all connected power supply units must total the equivalent of a power source
with limited power (LPS limited power source).
Never connect the device to AC voltage.
Never operate the device with DC voltage higher than 28.8 V DC.
4.4

Grounding

35 mm DIN rail
A functional grounding can be established by connecting a cable from terminal 3 to the DIN
rail, , for example. Such a cable should be kept as short as possible. Grounding is, however,
not necessary for interference-free operation.
4.5

Twisted pair cable

Recommendation
● Cable quality at least CAT 5
● Standard cables and IE FC RJ-45 Plug 180 connectors that can be assembled in the field
● Preassembled cables such as TP Cord RJ-45 0.5 m for connecting the CSM 1277 to the
Compact Switch Module CSM 1277
Operating Instructions, V. 1.20, A2B00079397B
WARNING
for connection of the S7-1200 station to the LAN, for example over greater distances.
CPU etc.
Mounting
4.4 Grounding
23