CANopen Device and application profiles

CiA standard profiles

With CiA 301, the fundamental CANopen specification, as a basis, a large number of CANopen documents have now been published that set out additional standards for devices or standard applications. In these supplementary standards (device and application profiles), the behaviour and parameters of standardised CANopen devices or applications are defined by means of corresponding items in the Object Directory. The aim of standardising device profiles is to ensure that devices of a particular class are interchangeable, thereby ensuring vendor independence.

Application profiles are intended to facilitate the integration of systems comprising equipment from different suppliers. Generic device profiles describe the interface of a single device, whilst application profiles describe all device interfaces that form part of an application. CANopen device profiles may also contain additional error codes, composite data types, device LEDs and many other elements. A device profile usually defines a standard mapping for the first four received and transmitted PDOs in order to fit within the Object Directory set as the default preference. In this way, a device can be used straight out of the box without the need to configure the communication first.

It is not possible to describe a CANopen device in all its possible variations. For this reason, all profiles provide for the definition of vendor-specific properties within what is known as the ‘vendor-specific profile’. This allows functions, parameters and properties to be described that are not included in the standard profile.

CiA 401 – I/O Modules

CiA 401 (Device Profile for I/O modules) is the best-known and most important CANopen device profile. This profile describes analogue and digital input and output interfaces and the ability to configure them. CiA 401 specifies an Object Directory for a maximum of 2,040 digital inputs/outputs and up to 255 analogue inputs/outputs. In addition to the standardised items for the current values, there are a number of supplementary OD entries to define the behaviour of these inputs/outputs.

CiA 402 – Drives and Motion Control

Another very important device profile is CiA 402, the device profile for drives with a CANopen interface (“Drives and Motion Control”). This profile applies to servo controllers, stepper motors and frequency converters. Like CiA 401, it is also based on a model of the behaviour of a drive. This drive model defines a state machine and supports, amongst other things, position determination, speed determination and the torque of the drive. Two of the most important – and therefore mandatory – Object Directory items are the “Control Word” and the “Status Word” for setting and reporting the control mode and status. They are defined first in every PDO.

Current profiles

The following table lists the currently defined CANopen device and application profiles:

A detailed description of these CANopen profiles can be found at can-cia.org.