What are IO-Link Device Profiles?

IO-Link IODD (IO Device Description) provides detailed information about IO-Link-enabled device such as the manufacturer identification, serial number, article number, operating states, electrical and mechanical characteristics, and much more. However, for many device types, process data, configuration parameters and functions are still not fully standardized. Device Profiles, which are continuously expanded and improved by the IO-Link Community, provide a solution.

Common device profile

IODD is a device description file for sensors and actuators. It contains information about identification, device parameters, process and diagnostic data, communication properties and other details. However, it is not uncommon that the parameter specifications differ between similar device types even from the same manufacturer. This can severely limit the reusability of parameter data or representation during visualization. To standardize access to IO-Link devices from the user controller applications, the IO-Link community has defined standardized device profiles for IO-Link devices.

The Common Profile is always supported in IO-Link devices and, as the lowest common denominator, provides uniform information about device identification and diagnostics (I&D) and firmware updates (Binary Large Objects (BLOB)). The Common Profile thus forms the foundation for all the device profiles and specifies the requirements of the IO-Link standard. It defines rules that all other profiles must follow, for example regarding the process data arrangement and description. 

Smart sensor profile

A smart sensor profile has been published at the end of 2011. It standardizes the behavior and the nomenclature of sensor parameters and facilitates the integration and handling of the compliant sensors. Neither the manufacturer nor the sensor type play a role in smart sensor profiles. This means that IO-Link devices can be integrated into the controller with significantly less effort and can be replaced as required without having to accept any restrictions in flexibility. The first version defined the mandatory function classes with identification, diagnostics and process data. A second version was published in 2019, in which the IO-Link community agreed on the following cross-technology classification of device classes:

  • Binary sensors with fixed switching point (Fixed ­Switching Sensors – FSS) -
  • Binary sensors with adjustable switching point (­Adjustable Switching Sensors – AdSS) -
  • Measuring sensors (Digital Measuring Sensors – DMS)

Easy device profile

The purpose of all profiles is for devices to only differ in their identification. Then, the PLC program can be used unchanged even if the device is replaced. This also enables commissioning without detailed knowledge of the individual device. The ultimate goal of the IO-Link community is to create a single profile for all devices, which is also suitable for standardization. 

Already in the works are:

  • a Smart Actuator profile,
  • a Lighting and Indication profile
  • and, more recently, a Smart Power Systems profile.
A call for experts has been launched for profiles for IO-Link safety devices and blob content.