CiA® 406: Profile for encoders

The CiA 406 profile series specifies the application interface for absolute rotary and linear encoders. The CiA 406-B document (still under development) based on the legacy CiA 406 document specifies the process data, the configuration parameters, and the diagnostic information. The mappings to classic CANopen (CiA 406-C) and to CANopen FD (CiA 406-F) are under development. The CiA 406-J document specifies the mapping to J1939-based networks.

The encoder manufacturers supply various markets with encoders implementing the same electronic interface according to CiA 406. Besides position and velocity values, the profile specifies also process data for acceleration and jerk values. Furthermore, the document describes several configuration parameters, e.g. the code sequence (complement) that determines the counting direction in which the output code is to be increased or decreased. The resolution parameter is used to configure a given number of steps for each revolution. In addition, the profile covers complete cam functionality with hysteresis.

The encoder profile specifies two operation modes:

  • Periodical mode: The current position value is sampled and transmitted periodically by means of the PDO event timer; the period is configurable.
  • Synchronous mode: The current position is sampled and transmitted after the reception of the SYNC message sent by the host controller or any other synchronization entity.

Three classes of CANopen encoders are specified:

  • Class 1 devices support normal resolution encoding and diagnostic functions without alarm and warning capabilities. Optionally Heartbeat and Layer Setting Services (LSS) are implemented.
  • Class 2 devices support all Class 1 functions. Additionally, scaling and preset functions are implemented as well as alarm and warning functions.
  • Class 3 devices support Class 2 functions and high-resolution position values. Optionally, they feature CANopen Safety. Heartbeat and LSS as specified in CiA 305 are mandatory.

Since CiA 406 version 4.0.0, the profile specifies the mapping of position values into SRDOs (Safety-Related Data Objects) as specified in EN 50325-5 (CANopen Safety). In addition, the CRC protection of configuration parameters is standardized.

The CiA 417 references partly the CiA 406 process data and configuration parameters for car position units. However, the object dictionary indices are different.

CiA 406-J: Mapping to J1939-based networks

The CiA 406-J specification enables manufacturers to implement the CANopen dictionary in a J1939-connectable encoder. The primary purpose of J1939-connectable encoders is the usage in body applications in trucks and mobile machines. The process data such as position value and velocity value are mapped into Parameter Groups (PGs) with registered PGNs (PG numbers). The process data such as position, velocity, and acceleration is mapped into parameter groups (PGs). The EPOS parameter group is used for normal resolution encoders and the EHRPOS parameter group can be used for 64-bit encoders. The speed and acceleration are carried in other PGs. Another PG maps both position and speed.

For configuration and diagnostic purposes CANopen SDO and Emergency services are mapped into standardized PGs (see CiA 510).

Title Details
CiA 301 version 4.2.0CANopen application layer and communication profile
DescriptionThis specification specifies the CANopen application layer. This includes the data types, encoding rules and object dictionary objects as well as the CANopen communication services and protocols. In addition, this specification specifies the CANopen network management services and protocols. This specification specifies the CANopen communication profile, e.g. the physical layer, the predefined communication object identifier connection set, and the content of the Emergency, Timestamp, and Sync communication objects.
PAS3.0 MiB2011-02-21Login
CiA 305 version 3.0.0CANopen layer setting services (LSS) and protocols
DescriptionThis document specifies the layer setting services (LSS) and protocols for CANopen. These services and protocols are used to inquire or to change the settings of three parameters of the physical layer, data link layer, and application layer on a CANopen device with LSS slave capability by a CANopen device with LSS master capability via the CAN network.
DSP1.9 MiB2013-05-08Login
CiA 406 version 4.1.0CANopen device profile for encoders
DescriptionThis document specifies the communication and application parameters for different types of linear and rotary encoders such as incremental and absolute, normal, and high resolution, single and multi-sensor (linear only) encoders. The document provides also operating principles of the encoders and specifies encoder output process values such as position, speed, acceleration and jerk. The document specifies also encoder CAM parameters. This document also specifies CANopen Safety parameters such as Safety position and Safety speed for encoders with CANopen Safety functionality (see EN 50325-5).
DSP2.1 MiB2019-06-01Login
CiA 406 version 3.2.0CANopen device profile for encoders
DescriptionThis document represents the CANopen device profile for incremental and absolute, linear and rotary encoders. Besides position, velocity, acceleration, and jerk output possibility complete cam functionality is covered. In addition, it is possible to handle multi-sensors through one CANopen device. All the above mentioned devices use communication techniques, which conform to those described in the CANopen application layer and communication profile specification /CiA301/. This document should be consulted in parallel to this profile.
PAS1.2 MiB2006-12-18Login