Siemens SIMATIC NET S7-1200 Compact Operating Instructions

Note
The previous device CSM 1277 with order number 6GK7277-1AA00-0AA0 had a di󹪜erent 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.
Note
If the CSM 1277 switch is supplied over long 24 V power supply lines or networks, measures are
necessary to prevent interference by strong electromagnetic pulses on the supply lines. These
can result, for example, due to lightning or switching of large inductive loads.
One of the tests used to attest the immunity of the switches to electromagnetic interference is
the "surge immunity test" according to EN61000-4-5. This test requires overvoltage protection
for the power supply lines. A suitable device is, for example, the Dehn Blitzductor VT AD 24 V
type no. 918 402, or a comparable protective element.
Manufacturer:
DEHN+SÖHNE GmbH+Co.KG Hans Dehn Str.1 Postfach 1640 D-92306 Neumarkt, Germany
WARNING
Never connect the device to AC voltage.
Never operate the device with DC voltage higher than 28.8 V DC.
WARNING
Power supply
The device is designed for operation with a directly connectable safety extra low voltage (SELV)
from a limited power source (LPS).
The power supply therefore needs to meet at least one of the following conditions:
• Only safety extra low voltage (SELV) with limited power source (LPS) complying with IEC
60950‑1 / EN 60950‑1 / VDE 0805‑1 or IEC 62368-1 / EN 62368-1 / VDE 62368-1 may be
connected to the power supply terminals.
• The power supply unit for the device must meet NEC Class 2 according to the National
Electrical Code (r) (ANSI / NFPA 70).
If the equipment is connected to a redundant power supply (two separate power supplies),
both must meet these requirements.
Installation
4.4 Power supply
Compact Switch Module CSM 1277
30 Compact Operating Instructions, 06/2022, A2B00079397-02

Siemens SIMATIC NET S7-1200 Specifications

General

Supply voltage	24 V DC
Protection class	IP20
Product type designation	S7-1200
Transfer rate	10/100 Mbit/s
Number of ports	4
Power consumption	2.5 W
Operating temperature	0 °C to 60 °C
Mounting type	DIN rail
Switching capacity	1 Gbps