IO-Link IO-Link is a manufacturer-independent point-to-point communication system used to connect sensors and actuators to an automation system. An IO-Link system consists of an IO-Link master and several IO-Link devices. The IO-Link master represents the interface to the controller or fieldbus level and communicates with the connected IO-Link devices. IO-Link is capable of processing switching signals of binary sensors, process values of analogue sensors and their parameters in a purely digital form based on a 24 V signal. This eliminates measuring value errors associated with the transmission and conversion of analogue signals. IO-Link can be used to transfer several process values or parameters of a device simultaneously via one unscreened standard cable. IO-Link is an internationally standardised fieldbus and controller independent interface.