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3 IO-Link information
IO-Link is a serial digital communication protocol intended to be used in automation technology. It
connects sensors, actuators and also measuring systems (IO-Link devices) to an automation system,
e.g. a PLC. In a way, IO-
Link provides for digitalization of the “last meter” of the communication link to
the sensors and actuators.
IO-Link is defined in the international standard IEC 61131-9. Part 9 specifies IO-Link under the term
“Single-drop digital communication interface for small sensors and actuators” (SDCI).
Where only binary states (on/off) or analog signals have been transmitted so far, it is now possible to
read status information from an IO-Link device and write parameterization information to an IO-Link
device. Now with this features, it is also possible to connect measuring systems to an IO-Link system.
IO-Link is not just another bus system, but a point-to-point connection between the IO-Link device and
a link device, namely an IO-Link master.
The IO-Link master communicates with the IO-Link devices, collects data from them and transmits the data
to the higher-level bus system (Fieldbus) or to the Industrial Ethernet.
Figure 1: System overview [Source: IO-Link Community]
IO-Link Community
c/o PROFIBUS Nutzerorganisation e.V. (PNO),
Haid-und-Neu-Str. 7,
D-76131 Karlsruhe,
Tel.:
++ 49 (0) 721 / 96 58 590
Fax:
++ 49 (0) 721 / 96 58 589