CANopen SDO Commands

Overview

WRITE_SDO and READ_SDO objects are used to send commands. The SDO abort code is used when the command is not successful.

WRITE_SDO Command

This table shows the header of the WRITE_SDO command:

Value (hex)	CIP generic message parameter
65	Class ID
40	Service Number
1	Instance
x	Length

This table shows the command data and the response data for the WRITE_SDO:

Value	Size	Parameter
Command data
0: PLC 1...4: DTM	SINT	Connect ID
[1...127]	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
[1...255]	INT	Length
User defined	SINT[...]	Data
Positive response data
[1...127]	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
0	INT	Status
Negative response data
[1...127]	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
≠0	SINT	Status
See table	SINT[4]	SDO abort code

READ_SDO Command

This table shows the header of the READ_SDO command:

Value (hex)	CIP generic message parameter
65	Class ID
41	Service Number
1	Instance
x	Length

This table shows the command data and the response data for the READ_SDO:

Value	Size	Parameter
Command data
0: PLC 1...4: DTM	SINT	Connect ID
[1...127]	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
[1...255]	INT	Length
Positive response data
[1...127]	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
0	INT	Status
User defined	INT	Length
Value requested	SINT[...]	Object value
Negative response data
0x2B	SINT	Node ID
User defined	INT	Index
User defined	SINT	Subindex
≠0	SINT	Status
See table	SINT[4]	SDO abort code

CIP™

(common industrial protocol) A comprehensive suite of messages and services for the collection of manufacturing automation applications (control, safety, synchronization, motion, configuration, and information). CIP allows you to integrate these manufacturing applications with enterprise-level Ethernet networks and the Internet. CIP is the core protocol of EtherNet/IP.

DTM

(Device type manager) Device driver running on the host PC. It provides a unified structure for accessing device parameters, configuring and operating the devices, and troubleshooting devices. DTMs can range from a simple graphical user interface (GUI) for setting device parameters to a highly sophisticated application capable of performing complex real-time calculations for diagnosis and maintenance purposes. In the context of a DTM, a device can be a communications module or a remote device on the network.

Refer to FDT.