S7-300 Digital modules

S7-300 Signal modules


Digital actuators and sensors can be connected to a SIMATIC S7-300 via digital modules. The extensive range of modules allows the most suitable signal module to be selected in each case.

Area of application

Digital input/output modules contain digital inputs/outputs for the automation system. Digital sensors and actuators can be connected to the automation system via these modules. Switches and 2-wire proximity switches (BEROs) can be connected to input modules, for example. Output modules are suitable for connection of solenoid valves, contactors, small motors, lamps and motor starters.


The use of digital input/output modules provides the user with the following advantages:

  • Optimum adaptation;
    since almost any combination of modules is possible, the number of inputs/outputs can be matched to suit the task in hand. Superfluous investments no longer exist

  • Flexible process connection;
    the wide variety of digital actuators and sensors facilitates connection of the automation system to the process

Design and functions

Digital input/output modules exhibit the following mechanical characteristics:

Compact design 
The rugged plastic housing features:
• Green LEDs for displaying the signal states at the inputs/outputs
• Slot for the front connector, protected by the front cover
• Labeling area on the front cover

Easy assembly
The modules are mounted on DIN rails and connected to adjacent modules via bus connectors. There are no slot rules, the input addresses are determined by the slots.

When used in the ET 200M distributed I/O station together with active bus modules, the modules can be hot-swopped during operation without affecting the other modules.

User-friendly wiring

The modules are wired by means of a front connector. When they are first plugged in, a coding element clicks into place so that the connector will only fit into modules of the same type. When the module is replaced, the front connector can be used in its fully-wired state for a new module of the same type.

Technical specifications

Technical specifications S7-300 digital modules