CiA® 406: Encoder profile

This device profile series specifies the application interface for absolute rotary and linear encoders. The most recent edition comprises four parts:

  • CiA 406-B: Functional behavior and parameters
  • CiA 406-C: Mapping to CANopen CC (classic)
  • CiA 406-F: Mapping to CANopen FD
  • CiA 406-J: Mapping to J1939

Part B based on the legacy CiA 406 document specifies the process data, the configuration parameters, and the diagnostic information. The encoder manufacturers supply various markets with encoders implementing the same electronic interface according to CiA 406 series. 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 taking hysteresis into account.

The encoder profile specifies two distinct 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.

Only one mode can be used at the same time.

Three classes of CANopen encoders are defined:

  • 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.

Any class can support CANopen Safety.

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

Besides the mapping to CANopen CC PDOs, Part C specifies also the mapping of position values into SRDOs (Safety-Related Data Objects) as according to EN 50325-5 (CANopen Safety). The CANopen Safety encoder application configuration is validated using the same CRC polynomial (CRC-CCITT) as for communication configuration (see EN 50325-5).

Part F specifies the mapping of encoder process data to CANopen FD PDOs. Three TPDOs are pre-defined. The mapping depends whether it is a single- or a multi-channel device. As in CANopen CC PDOs only position values are pre-mapped. Additional process data can be mapped by means of configuration. The maximum length of these PDOs are 64 byte.

Part J 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).

Additionally, CiA provides the legacy CiA 406 version 4.1.0 specifying the functional behavior including process data and configuration parameters as well as the CANopen CC mapping. This predecessor approach is currently in many encoders implemented. It complies widely with CiA 406-B and CiA 406-C.

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 server capability by a CANopen device with LSS manager capability via the CAN network.
DSP1.9 MiB2013-05-08Login
CiA 406-B version 1.0.0Encoder device profile - Part B: Functional behavior and parameters
DescriptionThis document specifies the functional behavior as well as 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. This includes encoder output process values such as position, speed, acceleration and jerk, and encoder CAM parameters. Additionally, safety-related parameters such as safety position and safety speed for encoders are specified. The mapping into Process Data Objects (PDO), Safety-related Data Objects (SRDO), and Parameter Groups (PG) is not in the scope of this document.
DSP1.6 MiB2022-12-07Login
CiA 406-J version 1.2.0Encoder device profile - Part J: Mapping to J1939
DescriptionThis document specifies the mapping of CiA 406-B process data into J1939 parameter groups. This includes the specification of parameter groups and the configuration by means of the CAM11 and CAM21 parameter groups specified in the CiA 510 document.
DSP263 KiB2022-12-07Login
CiA 406-C version 1.0.0Encoder device profile - Part C: CANopen mapping
DescriptionThis document specifies the CANopen communication and mapping parameters for encoders compliant with the CiA 406-B specification. This includes the PDO mapping and the optional SRDO mapping.
DSP753 KiB2022-12-07Login
CiA 406-F version 1.0.0Encoder device profile - Part F: CANopen FD mapping
DescriptionThis document part specifies the CANopen FD communication and mapping parameters for encoders compliant with the CiA 406-B specification. This includes the PDO mapping.
DSP492 KiB2022-12-07Login
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).
DS2.1 MiB2022-12-23Login