User Manual

en_BA_U500_UR18_Gen2_IO-Link.docx 5/43 Baumer Electric AG
04.04.2019/ Frauenfeld, Switzerland
2.2 IO-Link Communication Mode
The IO link communication mode is initiated by the master (PLC) with a standardized command sequence,
this sequence is called “wake-up”. After successful completion of the wake-up sequence the IO link
communication starts.
Data is the most important basis for process and product optimization. With the help of IO-Link, valuable
additional data can be made accessible. Sensor and Master can exchange two different types of data (cyclic
and acyclic data).
More information can also be found here.
2.2.1 Cyclic data
Transmitted in real time. They are used for process control in the automation system. These can also be
transferred to other IT systems via IO-Link.
2.2.2 Acyclic data
Through this data stream, sensors (IO devices) can be parameterized. Additionally this data stream also
allows to transmit data for identification and analyzation. The figure below shows the different types of data
and their value for the application.
Figure 2 Different IO Link data streams
2.3 IO-Link Device Description (IODD)
Each IO-Link Device has a device description file, the so-called IODD (IO Device Description). This contains
data about the manufacturer, article number, functionality, software version etc., which can be easily read out
and further processed by the automation system. Each device, i.e. each sensor, can be uniquely identified
both via the IODD and via an internal device ID. The identification data of the sensor also includes device or
application descriptions that can be freely assigned by the user. The IODD consists of several files: a main file
and optional external language files (both in XML format), as well as image files (in PNG format).