Siemens SIMATIC NET S7-300 Operating Instructions

5.1 Possible sources of problems and how to deal with them
Fuses
Note
The CSM 377 compact switch module has a resettable fuse / PTC. If the fuse triggers (all LEDs are
o󹪜 despite correctly applied power supply), the device should be disconnected from the power
supply for approximately 30 minutes before turning it on again.
LED display when voltage drops
If the power supply sinks below approximately 14 V, the internal power supply switches o󹪜, the
L-LED and all port LEDs go o󹪜. The functionality of the CSM 377 is no longer available.
Device defective
If a fault develops, please send the device to your SIEMENS service center for repair. Repairs on-
site are not possible.
Maintenance and troubleshooting
5.1 Possible sources of problems and how to deal with them
Compact Switch Module CSM 377
34 Operating Instructions, 06/2022, A2B00073499-02

Siemens SIMATIC NET S7-300 Specifications

General

Product Type Designation	SIMATIC NET S7-300
Mounting	DIN rail mounting
Protection Class	IP20
CPU Models	Various models available (e.g., CPU 312, CPU 314)
Communication Interfaces	MPI, PROFIBUS DP
Power Supply	24 V DC power supply required. Different power supply modules available.
I/O Modules	Digital input modules, digital output modules, analog input modules, analog output modules
Programming	STEP 7 software
Supply Voltage	24V DC or 120/230V AC (depending on model)
Digital Inputs	Available via digital input modules
Digital Outputs	Available via digital output modules
Analog Inputs	Available via analog input modules
Analog Outputs	Available via analog output modules
Communication Functions	MPI, PROFIBUS DP, Ethernet (depending on model)
Protocols	MPI, PROFIBUS DP, TCP/IP (depending on model)
Operating Temperature	0°C to 60°C
Storage Temperature	70 °C
Memory	Depends on CPU model (e.g., 32 KB to 1.5 MB)