SIEMENS S7-300 I/O modules Digital modules

OverviewS7-300 Digital modules

  • Digital inputs and outputs
  • For flexible adaptation of the controller to the respective task
  • For connecting digital sensors and actuators


Digital input/output modules possess digital inputs/outputs for the automation system. Digital sensors and actuators can be connected via these modules.

Use of the digital input modules offers the following advantages for users:

  • Optimum adaptation;
    the number of inputs/outputs can be adapted to the respective task using optional combination of modules. Superfluous investments no longer exist
  • Flexible process connection;
    the automation system can be connected to the process using many different digital actuators and sensors


Digital input/output modules feature the following mechanical characteristics:

Compact design

The rugged plastic housing contains:

  • Green LEDs for indicating the signal states on the inputs/outputs
  • Socket for the front connector, protected behind the front door
  • Labeling field on the front door.
  • Connector pin assignment for the wiring on the inside of the front door.

Easy installation

The modules are mounted on the DIN rail, and connected to the adjacent modules by means of bus connectors. There are no slot rules, the addresses of the inputs are determined by the slot.

When used in the ET 200M distributed I/O system together with active bus modules, hot swapping of the digital input/output modules is possible without any reaction. The remaining modules continue to operate.

User-friendly wiring

The modules are wired via a front connector. When the module is connected for the first time, a coding latches in the connector so that the connector now only fits onto modules of the same type. Upon module replacement, the front connector can be used fully wired for a new module of the same type. This prevents a wired front connector from accidentally being plugged into the wrong module during replacement.