CiA® 445: CANopen device profile for RFID devices

The CiA 445 profile specifies the CANopen interface for simple and intelligent RFID (radio frequency identification) devices, which read or write data from/to RFID transponders (also known as RFID tags). When implementing the profile, RFID device manufacturer may supply diverse application fields using the same electronic CANopen interface implementation and simply adapting the required application functionality. A system designer may choose between CANopen devices from different manufacturers implementing the same profile-compliant functionality. For development, analysis, and maintenance of the devices, off-the-shelf CANopen tools may be used.

The profile specifies four classes of RFID devices ranging from an RFID reader device with single transponder and single supported frequency to a multiple RFID reader/writer device with multiple transponders and multiple supported frequencies. Generally, select commands (determine target tag groups), inventory commands (identify individual tags from a group), and access commands (read/write tag memory fields, lock the tag or kill the tag) are necessary to control RFID readers. The defined application parameters include the external trigger command (starts reading or writing), the events indicating weather the transponder is entering/leaving the reading area (inclusive the appropriate counter), the transponder amount in the reading area, as well as the errors which occurred during the last read or write access.

During the reading access, the data received from the different tags is stored in a FIFO-like way (first in first out) in the manufacturer-specific application software of the RFID reader. A typical data set with information read from a certain tag includes the FIFO entry number, transponder type, received data, data length, unique identifier, time of reading, as well as the diagnostic information if the reading access failed. To make one or several entries of this FIFO visible to the CANopen network, several objects (arrays) are defined in the CANopen object dictionary. The same sub-indices (up to 254) of these arrays compose one data set. Hence, up to 254 selected FIFO-memory entries may be represented in the CANopen object dictionary and may be read via the CANopen network. By means of a FIFO control word and FIFO commands, it is possible to switch view on the FIFO entries (display selected data sets) or to execute pre-defined commands (e.g. erase) of selected FIFO entries.

The specification also defines several application objects (arrays) used for writing information to a certain tag. The same sub-indices of these arrays compose a set of parameters. Such a data set contains information about the transponder type, destination address (to which is written within the tag) and source address (index and sub-index of data source), data length, trigger (event initiating writing), write mode (e.g. write data, activate protections, erase data, kill tag), key (unlocking the writing area), and select channel (for multiple RFID devices). Furthermore, several objects are specified representing the data source for writing e.g. Unsigned8, Unsigned16, Unsigned32, domain of data or a path of file (represented as a string).

The profile specifies no default PDO mapping. Instead, for read and write direction a simple access to the tag information is specified. The information is read from or written to PDO-mappable objects of data type Unsigned8, Unsigned16, Unsigned24, Unsigned32 or Unsigned64.

Devices compliant to the profile use connectors and the recommended pinning according to CiA 106. The physical layer definitions follow those in CiA 301. For node-ID assignment via the CANopen interface (e. g. for IP67-rated devices), it is recommended to use the CANopen layer setting services (see CiA 305). Support of the emergency message and the heartbeat functionality is mandatory.

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 445 version 1.1.0CANopen device profile for RFID devices
DescriptionThis document specifies the CANopen interface for simple and sophisticated radio frequency identification (RFID) devices. This includes the specification of the physical layer, the data link layer, and the application layer as well as the specification of process data, configuration parameters, and diagnostic information. This includes commands and possibilities to control an RFID reader via the CANopen network.
DS1.3 MiB2022-04-29Login
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 106 version 1.1.0Connector pin-assignment recommendations
DescriptionThis document recommends the connector pin-assignment for CAN interfaces. This includes the CAN_H and CAN_L pins, the ground pin, and the power supply pins.
TR0.9 MiB2023-07-11Login