General
Product type	Signal board
Manufacturer	Siemens
Inputs	2 DI
Outputs	2 DO
Operating voltage inputs	24 V DC
Operating voltage outputs	24 V DC
Compatibility	SIMATIC S7-1200 CPU (including CPU 1211C)
Mounting method	directly on front side of CPU

The Siemens SIMATIC S7-1200 Digital I/O Signal Board 6ES7223-0BD30-0XB0 is a compact expansion module for the S7-1200 Basic Controller series. It extends the digital input and output functions by two channels each, with both inputs and outputs operating at 24 V DC. The signal board is directly plugged onto the front side of the controller, enabling a flexible and space-saving expansion, even with smaller CPU models such as the CPU 1211C. It thus serves as an alternative to larger signal modules when only a few additional I/O points are required.

Applications
This signal board is suitable for applications in industrial automation where a compact extension of control functions is needed. It is commonly used in smaller systems where the CPU is already installed and only a small number of additional digital inputs and outputs need to be added. The direct mounting on the CPU front side reduces space requirements in the enclosure and simplifies installation.

Functions and Features in Detail
The module provides two digital inputs (2 DI) and two digital outputs (2 DO), with both inputs and outputs designed for an operating voltage of 24 V DC. The inputs are intended for processing digital signals from sensors or switches, while the outputs can be used to control relays, drives, or other electrical loads. Signal transmission occurs via the integrated interface of the controller, eliminating the need for additional cabling.

Technology Explained Simply
The signal board functions as an integrated extension of the CPU, with communication taking place via the internal bus lines of the controller. The inputs are designed to process 24 V DC signals, which is common in industrial practice. The outputs also supply 24 V DC, allowing direct connection to electrical loads. Direct mounting on the CPU front side requires no additional mounting components, making installation quick and easy.

Compatibility and Accessories
The signal board is compatible with various CPU models from the SIMATIC S7-1200 series, including the CPU 1211C. It can be combined with other signal boards such as the 6ES7223-1BH32-0XB0 (8DI/8DO) or the 6ES7223-1BL32-0XB0 (16DI/16DO) to increase the number of I/O points. Additionally, plug-in couplers such as the 3RQ4118-2AM00 or screw connection couplers such as the 3RQ4118-1AM00 are available to simplify wiring. The use of terminal blocks such as the 6ES7292-1BF30-0XA0 can help organize the I/O signal connections within the enclosure.

Mounting and Installation
Mounting is achieved by directly plugging the signal board onto the front side of the CPU. No additional mounting or fastening is required. The electrical connection is made via the integrated interface of the controller. Wiring of inputs and outputs is done through the designated connection points, and the use of spring-cage or screw connection couplers can facilitate installation.

Operational Advantages
The signal board offers a cost-effective and space-saving solution for expanding I/O functions. Direct mounting on the CPU front side reduces space requirements in the enclosure and simplifies installation. The use of 24 V DC for both inputs and outputs allows direct connection to common industrial sensors and actuators. Compatibility with various CPU models increases flexibility in system design.