Basics concepts, Dictionary and Family

CANopen Profilesby Nguyen Hoang Anh

PFIEV K57

What is CANopen? Wikipedia definition:

“CANopen is a communication protocol and deviceprofile specification for embedded systems used inautomation.

CANOpen is the communication protocol that is used by the G-MAS and drives. It has been standardized by CiA – CAN in the Automation organization.

Every CANOpen device has an object dictionary a list of supported objects that can be read from and written to. These objects indicate and change the device behavior.

Basic Terms One of the most important

properties of CANopen is the provision of a standardized device description in the form of the so-called "object dictionary".

This is based on a "table" (device object dictionary), which has the same structure for all types of devices.

An OD object has a 24-bit address, made up of the 16-bit index and 8-bit subindex

Access to device’s data, parameters and functions of a device based on a logical addressing scheme

Object Dictionary (OD) Index, the 16-bit address of the object in the dictionary Object name, a symbolic type of the object in the entry,

such as an array, record, or simple variable Name, a string describing the entry Type, gives the datatype of the variable (or the datatype of

all variables of an array) Attribute, which gives information on the access rights for

this entry, this can be read/write, read-only or write-only The Mandatory/Optional field (M/O) defines whether a

device conforming to the device specification has to implement this object or not

Object Dictionary (OD)

Object Dictionary (OD) CAN open defines device profiles for typical devices:

Specification of the most important parameters, data andfunctions per device type

CANopen-compatible devices are interchangeable at the basic functionality level

The object dictionary is sub-divided into standardized areas of 4096 entries each: 1000-1FFF: communication area/communication profile 2000-5FFF: manufacturer-specific device objects 6000-9FFF: device profiles A000-AFFF: network variables (NWV)

Object Dictionary (OD)

The communication area of the object dictionary contains all parameters that concern the communication behavior. only a few entries themselves are mandatory; these are the entries [1000sub00], [1001sub00], [1018sub00] and [1018sub01].

Device Profiles Although the object dictionary concept allows for

structuring the data that needs to be communicated, there is still something missing: Which entry in the dictionary is used for what? The solution is simple: First of all, there are a few mandatory

entries that all CANopen nodes must support. These include the identity object with which a node can identify itself and an error object to report a potential error state. Additional entries are specified by device profiles. Device profiles describe all the communication parameters and object dictionary entries that are supported by a certain type of CANopen modules. Such profiles are available for generic I/O modules, encoders and other devices.

Electronic Data Sheet (EDS) The data type and meaning of each OD object must be

known bythe configuration tools ⇒ an electronic data sheet (EDS) describeseach object dictionary entry address (index/subindex), param. name, data type,

access type anddefault value

An EDS is an ASCII file in WIN.INI format, which is used by CANopen configuration tools to allow the user to configure devices.

Electronic Data Sheet (EDS) CANopen data types :

bytes, words and double words, signed/unsigned ASCII and Unicode strings one-bit boolean data type 32/64 floating point types in accordance with IEEE 754-1985 Time_of_day: millisec since midnigh (28 bits) and the days since

1/1/1984 (16 bits) byte stream of undefined length (domain

Family CANopen devices are divided into families. Each family has its own object dictionary and specific

definitions. The most basic family is the DS301 family. All other families are derivatives of this family. DS301 – The basic family of CAN devices. It holds the

basic terms and the basic object dictionary that DS301 devices need to support (like object 0x1000 “device type”).

Family DS301 Family Derivatives:

DS402 Servo Drives – For example Elmo drives, need to support additional objects, for example: actual position – object 0x6064.

DS401 IOs – These devices have Digital/Analog Inputs/Outputs, user may write to outputs and read from Inputs. These devices may support objects like write outputs – object 0x6200.

DS406 encoders - These devices send position via a predefined method. User may use these positions for application purposes

Thank You

Helpful Links - Basichttp://

www.esacademy.com/en/library/technical-articles-and-documents/can-and-canopen/embedded-net

Introduction to the Controller Area Network (CAN - Texas Instruments) www.ti.com/lit/an/sloa101a/sloa101a.pdf