July 16, 2024
IO-Link Technology for Industrial Applications


IO-Link technology was introduced over a decade ago and the number of IO-Link devices have been expanding and more devices are deployed. The technology continues to evolve with new specifications and standards, including IO-Link Safety and IO-Link Wireless. The IO-Link Community and the working groups have been continuously adding enhancements to IO-Link as it evolves.

This ARC Insight covers various aspects of IO-Link, including an overview of IO-Link technology, IO-Link devices, IO-Link Safety and IO-Link Wireless. It also looks at users’ challenges and requirements, key features and benefits of the technology, and provides recommendations for technology suppliers and users.

Current Situation

In today’s data-driven environment, end users want smarter machines and more functionality than what traditional sensors provide. The shortage of skilled personnel is a key reason. With the exodus of experienced workers, much of the operational, procedural, and maintenance knowledge required to operate machines is going out of the door. Smart sensors offer a path to the digital capture of information, which can enable applications such as predictive maintenance (rather than reactive or preventive maintenance). But the implementation of smart sensors is just not enough. The information provided by these sensors must get to the right people, at the right time, and in the right context to be effective.

IO-Link Technology for Industrial Applications

IO-Link has been around over a decade and about 27 million IO-Link nodes have been deployed worldwide. IO-Link is a short distance, bi-directional, digital, point-to-point, wired and/or wireless, industrial communications networking standard, described in IEC 61131-9. This standard specifies a single-drop digital communication interface technology (SDCI) for sensors, actuators, and mechatronics. It extends the traditional switching input and output interfaces as defined in IEC 61131-2 to a point-to-point communication link using coded switching. The point-to-point communication is based on well-established 3-wire sensor and actuator connections. The technology enables cyclic exchange of digital input and output process data as well as acyclic exchange of parameter and diagnosis data between a Master and associated devices. A Master can be coupled via gateway to an upper-level system such as a fieldbus connected to a programmable logic controller.

IO-Link Technology for Industrial Applications

The IO-Link technology standard is managed by PROFIBUS & PROFINET International (PI), which claims about 400 IO-Link community member companies. Most members are suppliers of factory and process automation products such as sensors, instrumentation, PLC, DCS, IPC and HMI.

According to IO-Link Community, despite delivery bottlenecks and other uncertainties due to the current pandemic, manufacturers of IO-Link products using technology from PI have reported positive revenue figures for 2021. Last year, 6.3 million f IO-Link devices were installed, bringing the total number of installed devices to over twenty-seven million.

Salient Features of IO-Link:

  • Fieldbus independent and can be integrated into all fieldbus systems.
  • Relies on standards such as M12, M8 or M5 connectors and three-wire cables.
  • Enables an extended diagnosis of sensors and actuators and parameter setting due to bidirectional communication.
  • Available with communication speeds of 4.8, 38.4 and 230.4 kBaud.
  • Enables the miniaturization of sensors and actuators.
  • Automated and offers remote maintenance of devices via the bidirectional communication.

IO-Link Safety

As the number of installed IO-Link devices has grown to twenty-seven million, the technology has been enhanced with more capabilities. With the release of the specification in 2017, IO-Link Safety is a key update, filling a gap for the implementation of safety over IO-Link.

The introduction of IO-Link Safety has made the technology even more attractive for industrial applications. New safety IO devices have been introduced that communicate safety signals directly over IO-Link. These devices extend the advantages of IO-Link into functional safety systems by facilitating high-density safety IO hubs, simplifying wiring, and seamlessly implementing more complex safety sensors. IO-Link Safety is an extension to IO-Link that uses an additional safety communication layer on top of both the Master and the device, thus Functional Safety (FS)-Master and an FS-Device have been developed that are approved by TÜV-SÜD.


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Keywords: Actuators, Factory Automation, Industrial Communication, Industrial Applications, IO-Link Safety, IO-Link Wireless, Smart Sensors, ARC Advisory Group.