Industrial processes can always be more efficient, but is that cost-efficient? Industrial automation is an important topic for many industrial companies to save costs and produce more efficiently. IO-Link makes it possible to be cheaper and more efficient!

What does IO-Link do?


Sensors are part of a whole system of equipment and machines in an industrial process. All parts must be able to communicate properly and quickly so that errors are prevented and processes that are already functioning properly run faster and more efficiently. IO-Link is the technology that makes this communication possible without the need for extra cables, etc. IO-Link lives up to its role in industrial processes, due to its easy integration into existing industrial setups and networks. This makes it the first I/O technology to be accepted as a world standard.

A typical IO-Link system

An IO-Link set-up consists of a controller, master and a slave device. The connection in this set-up is established through 3-wired or 5-wired interface cables..

The master is responsible for being able to connect a device to the IO-Link network on the one hand and for exchanging data with it between the device and the controller on the other. This data consists of data and parameters that must be communicated with each other.

The second component is the device. This can be a sensor, an actuator or both. These perceive data about units such as distance and temperature that has to be communicated with the controller in a cyclical manner. Through IO-Link, this information is converted and exchanged without interruptions and in real time (at the moment of perception). The output of this conversion is digital.

Types of IO-Link data and how it is exchanged

IO-Link communicates four types of data, of which the first two are transferred cyclically. With an example applications we will have a look at these data and its purpose: an ultrasonic level measurement in a water tank.  

1. Process data

Process data involves realtime data for controlling the connected device: the sensor, in this case. The master communicates control data (cyclically) to the sensor and then receives feedback.

These data packages will consist of the different water levels in the case of a level measurement with the ultrasonic sensor. 

2. Value status

Value status is validation of the process data. There will be checked if the communicated data is correct or includes mistakes/is incomplete. To execute this control of the process data (in sync) this data will also be communicated cyclically. 

So, the data about the different water levels are verified before they are transferred to the IO-Link master and then the PLC. 

3. Device data

Device data is information that is requested from the device (slave) by the IO-Link master and includes data such as the set parameters of the sensor, data for the identification of the sensor and information to establish diagnostic for issues.

In the case of our water tank example you can think of data about the specified measuring range and the network address of the sensor.

4. Events information

Events data concerns the communication of warnings and mistakes from the sensor to the master. An example is a defect or a bad functioning sensor, because of too much moist in the housing. These provide fast identification of problems and easier maintenance.


These are the types of data that can be communicated between the IO-Link master and the connected device (slave). This communication is directed via the communication ports of the IO-Link master. These ports can be configurated to your wishes and in the right application to function in one of the next modes: 

  • IO-Link mode - in this mode the port is used for IO-Link-communication between the master and a sensor.
  • DI-mode - in this mode the port functions as a digital input.
  • DQ-mode - in this mode the port functions as a digital output.
  • Deactivated - This mode is for turning off an unused communication port.  


Is IO-Link something for your company?

Not sure yet whether to make the switch to IO-Link or would you like to know how IO-Link can work for you? Contact us by phone: +31 0416-378 239. You will receive advice on the integration of IO-Link based on your specific area of application. You can also ask for a free quote!

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