More information, increased process efficiency thanks to digital sensor data

Sensors precisely detect varied measured values. Already processing of measured values in the sensor generates valuable secondary information. Sensors with conventional analog or binary output signals are not capable of information exchange with control or IT systems. Standardized digital communication interfaces, however, can forward such secondary information for use in higher-level systems. The use of digital sensor data is not an end in itself but can significantly improve your business processes.

What is IO-Link?

Example of system architecture with IO-Link

IO-Link is the IO technology worldwide standardized in IEC 61131-9. It enables vendor-independent digital, bidirectional point-to-point communication. For doing so, sensors are interconnected to an IO-Link master by standardized 3-wire plug-in cables. IO-Link is available for varied sensor technologies and also integrates in miniaturized sensors. 

The IO-Link master clustering several sensors connects the controller via the respective fieldbus system. Furthermore, an Ethernet-based master connection (with OPC UA) enables direct communication between sensors and IT systems. IO-Link masters are available as a field device for decentralized installation or as a version for installation in control cabinets. Many manufacturers also offer controllers with IO-Link input terminals for direct implementation of the IO-Link master. The maximum cable length between sensor and master is 20 m. However, significantly longer sensor/controller connections are enabled by connecting a field master to the fieldbus system. This will provide you with maximum connection flexibility.

Your benefits

Cost-effective & reliable connection
Advanced setting options
Secondary data
Improved flexibility
Fast sensor exchange
Easy & safe usability

Secondary data

Data is the most important basis for process and product optimization. IO-Link makes valuable secondary data accessible:


Operating modes

SIO mode and IO-Link mode

Each IO-Link master port can be operated either in SIO mode (standard in-out mode) or in IO-Link mode for information processing of any sensor. Sensor function in SIO mode is like the conventional counterpart. Measured values and switching states are transmitted to the controller via digital or analog outputs. In IO-Link mode, the digital sensor output is used as a bidirectional serial interface for both measurement and diagnostic information exchange. This mode also enables sensor reconfiguration.

By default, every cycle provides 2 bytes of process data. Users may also select larger data packages (frame types). This allows for transmission of higher volumes of process data with a length of up to 32 bytes within a correspondingly slower cycle time.

Dual Channel




Some sensors feature one or more dual channels for transmission of additional input and output signals in parallel to the IO-Link channel. This enables implementation of different control concepts.


Each IO-Link device comes with a device description file, the so-called IODD (IO Device Description). The IODD includes data about manufacturer, product number, functionality etc. for convenient user readout and processing. Each device or sensor provides its unique identification in both the IODD and the internal device ID. It consists of several files: main file and optionally external language file (XML format), as well as image files (PNG format).

IO-Link Glossary

Here you will find more detailed descriptions of IO-Link functions as well as term definitions.
To the IO-Link glossary



Brochures / Catalogs

You may also be interested in

To the top