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 303-1. 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.

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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.
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public3.4 MiB2011-02-21Login
CiA 445 version 1.0.0CANopen device profile for RFID devices
DescriptionThis device profile specifies the CANopen interface for simple and intelligent radio frequency identification devices.
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DSP0.9 MiB2007-08-23Login
CiA 303-1 version 1.9.0Recommendation - Part 1: Cabling and connector pin assignment
DescriptionThis document provides device and network design recommendations for CANopen physical layer. Additionally, it provides the guidelines for selecting cables and connectors for use in CANopen systems.
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public563 KiB2017-09-18Login
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. The following parameters may be inquired or changed: Node-ID of the CANopen device, bit timing parameters of the physical layer (bit rate), LSS address compliant to the identity object (1018h).
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DSP2.0 MiB2013-05-08Login