Basics of IO-Link 

IO-Link is a point-to-point communication protocol. A point-to-point connection is a communications connection between two separate endpoints or nodes.

It is bi-directional, meaning it works two ways and works over a short distance.

It is primarily used to communicate with sensors and actuators in factory automation processes.

Sensors and actuators are usually connected via Fieldbus connections, allowing them to be in remote locations.


With IO-Link, the field devices, Like actuators or sensors, connect to a ‘Master’ device that communicates to a controller, usually using a PLC (Programmable Logic Controller).

The connection between the IO-Link master and the device field is established via a three wires cable. (distance do not excide 20 meters long)

The master device is able of processing both digital and analog signals. Its versatility means it is able of integrating into existing systems also it can communicate using the Modbus, Profibus, and Profinet ...

The IO-Link master establishes the connection between the automation system devices & the IO-Link. As a component of an I/O system, the IO-Link master is installed either in the control enclosure or directly in the field as remote I/O.

An IO-Link master can have multi-channels or multi ports. it can be connected to each port, in other way IO-Link is a point to point communication and not a Fieldbus.