Terminology » CANopen Bus Frame Analysis & Packet Data Logger Tool

CANopen Bus Frame Analysis & Packet Data Logger Tool

automotive canopen frame protocol analyzer tool

Introduction : The CANopen protocol, built atop the standard CAN bus, enables interoperable, vendor independent device communication with a well defined frame structure.

CANopen Frame Structure

CANopen is based on standard CAN frame. It includes 11 bit or 29 bit identifier, control bits and up to 8 bytes of data. CANopen Communication Object Identifier (COB-ID) is specific type of identifier which splits 11 bit ID into 4 bit function code and 7 bit node ID.

CANopen Frame Structure

Field	Size	Description
Function code	4 bits	This field specifies the type of message.
i.e. it defines protocol or service type (e.g., NMT, SDO, PDO).
Node ID	7 bits	Identifies the specific device on the network, allowing for up to 127 nodes (1-127, with 0 often used for broadcast). It indicates sender or receiver.
Control bit (i.e. RTR)	1 bit	These include the Remote Transfer Request (RTR) bit, which is used in CAN to indicate if the frame is a data or remote frame.
DLC (Data Length Code)	4 bits	These include the Remote Transfer Request (RTR) bit, which is used in CAN to indicate if the frame is a data or remote frame.
Data	0 to 8 bytes	The actual payload of the message, which can be 0 to 8 bytes long.
CRC	16 bits	An error-checking field to ensure data integrity during transmission.
End of Frame	7 bits	Marks the end of the CAN frame.
IFS	3 bits	Inter Frame Spacing, 3 recessive bits

CANopen Data logger tool

Following table mentions some of the popular data logger tool manufacturers used to analyze CANopen protocol frames and their fields.

Manufacturers	Product with features
CSS Electronics	CANedge2 Logger : Supports 2 × CAN (and LIN) channels; CANedge1 Logger : Dual high-speed CAN / LIN (supports CANopen traffic) ; CANedge3 Logger : Same 2 × CAN + 2 × LIN channels as other CANedge loggers, with CANopen capability.
Kvaser AB	Kvaser Memorator 2xHS v2 : Supports 2 x CAN channels, Supports high speed CAN; can capture CANopen frames.
Influx Technology	ReXgen 2 CAN / LIN Logger : 2 × CAN (or CAN FD) + LIN support, Supports CANopen (and other CAN based higher layer protocols) since it records raw CAN bus frames.
Microport Computer Electronics Inc.	X-Analyser : Monitor, log, simulate CAN and higher-layer protocols (CANopen, LIN, J1939).
Embedded Systems Academy (esacademy.com)	CANopen Diag : Handheld diagnostic / test device for CANopen networks

Summary: By leveraging a CANopen packet data logger tool, engineers and network architects gain full traceability of every frame from object dictionary accesses via SDO, to cyclic and event driven PDO traffic and NMT state changes allowing efficient troubleshooting,