IODD
The IODD, or IO Device Description, is a data file that describes IO-Link sensors and actuators. It tells you who the device is, what it can do, the data it uses for process and diagnostics, how to configure it, and how engineering tools should talk to it. IODDs use XML files for the main description and optional language files, plus PNG images for graphics. The format follows ISO 15745, the standard for open systems in industrial automation.
An IODD combines the device profile and the communication network profile in one file. It defines two main parts: DeviceIdentity and DeviceFunction. DeviceIdentity contains user-facing text and IDs used to automatically identify devices in a plant. DeviceFunction holds information that isn’t part of the communication profile, such as device parameters, process data, diagnostics, and how the user interface should look and behave.
The IODD can describe product variants that share the same parameters and data but have different order numbers. This helps reduce the number of required device descriptions and IDs. The embedded communication network profile can be swapped, so the same IODD can describe devices with different interfaces. Text can be provided in multiple languages with language lists; usually the main file includes all lists, but translations can be kept in separate language files to keep the main file unchanged.
Standard IO-Link data are defined in IODD-StandardDefinitions[version].xml and are referenced by the IODD rather than repeated. The IO-Link Consortium provides the IODD specification, guidelines, and the IODD Checker. The current IODD version is 1.0.1, which covers IO-Link 1.0 and 1.1 in compatibility mode. In the future, IODD 1.1 will cover IO-Link 1.1 without replacing the 1.0.1 file. The IODD Checker tests both schema compliance and other IODD rules that XML alone can’t verify; after passing, the IODD is stamped. Engineering tools only accept stamped IODDs.
Tools and community resources offer an IODD Finder to help engineers pick the right IODD for a device.
This page was last edited on 2 February 2026, at 12:51 (CET).