IO-Link FAQs and glossary

Device that converts electrical signals into kinetic energy.

An A port has an integrated, low-current power supply for devices; a B port allows a second isolated supply for outputs.

Data that is only transferred from the controller after a request (e.g. parameter data, diagnostic data).

Data that goes in both directions (from and to the IO-Link master). Thus, the sensors can be configured and read during running operation.

IO-Link data transfer rates. Up to 32 bits can be transferred between IO-Link device and IO-Link master per cycle. With COM1 they are transmitted at 4.8 kBit/s, with COM2 at 38.4 kBit/s and with COM3 at 230.4 kBit/s.

A device can be a sensor, an actuator or a hybrid device. It is a passive participant and only replies at the master's request.

Digital input / output.

Device Type Manager (manufacturer-specific driver).

When using IO-Link the user receives both input and output data via the port of a sensor/actuator device. The typical differentiation of the port as input/output no longer applies. In standard mode without IO-Link every port of an IO-Link capable device can still be configured as input or output.

The device can signal an incorrect operating status to the master per event. This is done by setting a bit in the interface. The master reads this event with a classifying error code.

Field Device Tool (e.g. ifm Container)

Device master file - describes an interface to the device which is to be connected to the fieldbus. GSD files are available as files and provided by the device manufacturer.

Operating and observation device of the automation system (Human Machine Interface).

In contrast to the gateways hubs establish connections between two identical interfaces; known are USB hubs.

A device combining both sensor and actuator functions.

The international standard IEC 61131 deals with the basics of programmable logic controllers. Part 9 describes IO-Link under the designation single-drop digital communication interface for small sensors and actuators (SDCI).

Electronic device description (IO device description).

Field device that is monitored and controlled by an IO-Link master.

Establishes the connection between a higher-level fieldbus and the IO-Link device. The IO-Link master monitors and controls the IO-Link devices.

An MES is a level of a multi-layer process-oriented production management system. It distinguishes itself from similarly efficient systems for production planning, i.e. ERP systems (Enterprise Resource Planning) by direct connection to the distributed systems of process automation. The MES allows production processes to be managed and controlled in real time. This includes conventional data acquisition and data preparation such as production data acquisition (PDA), machine data acquisition (MDA) and personnel data acquisition, as well as all other processes immediately influencing the production process.

An IO-Link communication channel.

An IO-Link master to IO-Link specification 1.1 can act as parameter setting server for the IO-Link device.

A point-to-point connection is a direct, immediate connection between two points, places or devices.

Device that detects and converts physical values into electrical quantities.

Standard Input Output: This mode is used to operate conventional digital devices connected to IO-Link master ports and IO-Link sensors used without IO-Link structure.

A PLC is an industrial computer used to control a machine or system and programmed on a digital basis. The user programs a PLC according to the requirements of his system. The peripheral signals are read or provided via input/output modules or fieldbus masters and decentralised fieldbus slaves.

Bus participant that does not communicate independently but only replies to requests from the master.

The conversion time is the sum of the time the A/D converter needs to record the measured value and the time needed to process the measured value and the diagnostics and wire-break monitoring information in the module.

Data that is transferred automatically and at regular intervals (process data, value status).

In the context of controllers, the cycle time means the processing of the program from reading of the inputs to the provision at the outputs. In the context of communication systems, the cycle time is the time until all data has been exchanged with all participants and the cycle starts again. For IO-Link, it varies depending on the transmission rate. With COM3, a complete transmission cycle takes 0.46 milliseconds. With COM2, the cycle time is 2.3 milliseconds.