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  1. IO-Link benefits
  2. System overview
  3. Trends

IO-Link trends

IO-Link has been developed by leading sensor, actuator and control manufacturers who constantly work to improve this innovative technology. Their focus is on key trends in the industry to ensure continued suitability for field use.



Via profile function blocks, the PLC can access the process values of IO-Link devices from different manufacturers online at any time, since the data is provided in a standardised way thanks to the 'Communication Specification' and the profile parameters stored in the sensor. Different sensor resolutions are also presented in identical form to the PLC.

Thanks to these standardised system properties, process, identification and diagnostic data can be accessed in a uniform way independently of the device. As a result, the integration into the control program is much easier and faster.

Using IO-Link, diagnostic data, configurations and functions of different devices can be standardised and made available in a uniform manner. To access this data, uniform blocks will be used in the PLC. From parameter setting to process value evaluation, complexity is significantly reduced for the user.

In addition, it is possible to implement manufacturer-specific diagnostics, extensions and functions to drive innovation. However, the result of this non-standard use is that devices of different manufacturers are no longer comparable and universally applicable.

IO-Link Safety

Over the years, IO-Link has become established as a sensor/actuator communication system. To benefit from IO-Link in the field of safety technology, IO-Link Safety was developed, offering advantages such as reduced wiring, less conventional input and output cards needed, and use of analogue measured values for condition monitoring.


  • 5-pole M12 connectors and uniform software tools to integrate devices from different manufacturers
  • A central FS master for devices with different signal outputs
  • Compatibility with existing "standards" (e.g. OSSD)
  • Automatic check of the stored parameters, authenticity and I/O data structure during port start-up
  • Timing of the FS masters and FS devices according to the duration of the self-tests
  • Automatic transfer of parameters when replacing defective FS devices

The devices are connected to the IO-Link safety master (FS master). Devices from different manufacturers can be easily integrated via a uniform sensor/actuator interface (M12/5-pole). In the future, a universal software tool will be used for commissioning in order to reduce the number of special gateways when integrating devices. By using a compact FS master, you no longer need a high number of evaluation cards (input and output cards). This reduces wiring and allows for easy analogue value processing. Communication with the FS PLC takes place via the respective FSCP domain.

In compatibility mode, two separate OSSD channels are available as before. Two modes can be selected. Thus, sensors can be configured via IO-Link for easy setup and then operated in OSSD mode for reliable signalling of safety-relevant events.

To ensure safe operation right after start-up, the FS devices are automatically instructed by the FS master during port start-up to check the stored parameters, FSCPs, port numbers and the I/O data structure. IO-Link delays the readiness for operation of the FS masters based on the duration of these self-tests to compensate for the resulting delayed readiness of the FS devices.

Alternative safety products with IO-Link from ifm

With AL200S, ifm has launched its first safety product in the IO-Link environment. AL200S is a safe IO module for PROFIsafe with safe inputs and outputs. It is suitable for the connection of safe mechanical contacts and OSSD sensors.

Integration / Open Alliance 4.0

To enable seamless integration of IO-Link data via gateways, e.g. in fieldbuses such as PROFINET or EtherNet/IP, exchange formats between IO-Link and higher-level protocols and systems are defined and further standardised. This includes important exchange formats such as OPC UA or JSON to enable a connection to IT systems. To this end, leading manufacturers are working together in the 'Open Industry 4.0 Alliance', effectively driving progress to ensure ease of use and compatibility between products from different manufacturers.

The specifications defined by the IO-Link community demanding uniform, standardised data consistency from the lowest IO-Link field level to cloud-based services of the IT world resulted in a JSON-based exchange format. This encompasses both the definition of an API as the REST interface and data transport over MQTT. It includes data mapping, system behaviour and semantic definitions.

For seamless data transport into the world of IT, JSON (Java Script Object Notation) has established itself as a highly streamlined exchange format which can be used across all system boundaries. Through additional specification of the semantics, easy interpretation of the data is also made possible. This enables the seamless connection of the IO-Link level to MES/ERP systems, cloud-based services and applications outside classical PLC automation in general via the so-called 'Y path'.

In the 'Industrial Internet of Things' (IIoT) installations and machines get into contact with each other. In the cloud, each machine can be represented by a digital twin in a virtual factory. Even if they do not use the same language due to their own control systems, we establish the connection to the virtual factory. With the target to get information from their data. For efficient use, they give details on the state of the machines, on required maintenance, on potentials to increase productivity, on options to save energy and much more.

IO-Link Wireless

One of the key factors in the success of IO-Link is the easy wiring of intelligent sensors and actuators using standardised sensor cables. It will even be possible to dispense with this in the future to meet the increasing demand for fast and uncomplicated data exchange between an increasing number of participants. In the field of automation, mobile communications standards such as IO-Link, 5G or Wifi 6 form the building blocks for real-time M2M (machine-to-machine) communication. IO-Link technology, which was co-founded by ifm, enables remote access to different process values for diagnostics and condition monitoring without any conversion losses and completely controller and fieldbus-independent.

IO-Link is now wireless! This reduces the installation effort to a minimum. Real-time communication guarantees fast reaction times for immediate detection of process value fluctuations. In addition, defective components can be replaced in the shortest time without extensive wiring, thus avoiding long production downtimes. Moreover, downtimes in areas where cables usually wear quickly, such as on AGVs or robots, are excluded.


  • Automation of processes, e.g. by robots, drones or AGVs (high availability at maximum transmission speed and reduced range)
  • Non-time critical monitoring, e.g. of container levels for intelligent planning of waste collection routes (low data volume and current consumption with many participants as well as good energy efficiency with long range)
  • Diagnosis, parameter setting and visualisation of process data, e.g. for parameter adjustment in line with the material to be detected (high data volume with few participants and medium transmission speed with medium to small range)

The aim is to have up to five times as many IO-Link devices communicate with a master compared to standard cable connections - at a cycle time below 5 ms. In practical terms, this means that up to 40 devices will be able to communicate with one master via radio. For example, with three masters within one RF area, communication with up to 120 devices will be possible at the same time. Both cyclic data (process data) and acyclic data (on request data) can be transmitted. A range of up to 20 m is achieved between device and master.

Alternative wireless technologies with IO-Link from ifm

The io-key and the Bluetooth adapter are ifm’s first products in this direction. So it is already possible to access the process values of your applications wirelessly via GSM mobile network or Bluetooth. Wireless concepts are particularly important in process and time-critical applications, e.g. in automation, where many participants communicate with each other virtually in real time. ifm can look back on over 50 years of experience in this field of factory automation.