Siemens SIMATIC S7-300 Module data Hardware And Installation Manual

Appendix
S7-300 Programmable Controller Hardware and Installation
11-28 A5E00105492-01
11.3.6 How to protect digital output modules against inductive surge
voltage
Inductive surge voltage
Overvoltage occurs when inductive devices are switched off. Examples are relay
coils and contactors.
Integrated surge arrestor
S7-300 digital output modules are equipped with an integrated surge arrester.
Additional Overvoltage Protection
Inductive devices require additional surge arresters only in following cases:
• If SIMATIC output circuits can be switched off by additionally installed contacts
(e.g. relay contacts).
• If the inductive loads are not controlled by SIMATIC modules
Note: Request information on respective surge protection rating from the supplier
of inductive devices.
Example:
The figure below shows an output circuit that requires additional surge arresters.
Contact in the output circuit
Iinductivity requires
circuiting
(See the following figures)
Figure 11-8 EMERGENCY-OFF relay contact in the output circuit

Siemens SIMATIC S7-300 Module data Specifications

General

Series	S7-300
Manufacturer	Siemens
Protection Class	IP20
System	SIMATIC S7-300
Digital Inputs	Varies by module
Digital Outputs	Varies by module
Analog Inputs	Varies by module
Analog Outputs	Varies by module
Central Processing Unit	Varies by CPU model
Supply Voltage	24V DC or 120/230V AC
CPU Type	Varies (e.g., CPU 312, CPU 315, etc.)
Memory	Varies by CPU model
Communication Interfaces	MPI, PROFIBUS
Programming Languages	LAD, FBD, STL, SCL, GRAPH
Operating Temperature	0°C to 60°C
Storage Temperature	-40°C to 70°C
Relative Humidity	10% to 95% (non-condensing)