This specification uses the standardized CANopen interface for IEC 61131-3 programmable devices like PLC.

The devices use communication techniques which conform to those described in the CiA Draft Standard DS-301 (Application Layer and Communication Profile), Draft Standard Proposal DSP-302 (Framework for Programmable CANopen Devices) and Draft Standard Proposal DS-405 (Interface and Device Profile for IEC 61131-3 Programmable Devices). These documents should be consulted in parallel to this specification.

References:

- /DS-301/ CiA Draft Standard DS 301 V4.02 CANopen Application Layer and Communication Profile

- /DSP-302/ CiA Draft Standard Proposal DSP 302 V3.1 CANopen Framework for Programmable CANopen Devices

- /DS-405/ CiA Draft Standard Proposal DS 405 V2.0 CANopen interface and Device Profile for IEC 61131-3 Programmable Devices

In general, generating an application implements the handling of up to five interfaces:

 

This description just covers the interface:

A.  that means, the access to a CANopen communication system from within an IEC 61131-3 program based on calls to function blocks

 

This descricption does not (yet) cover the interfaces:

B.  utility functions for debugging, monitoring and network management

C.  interface between CANopen tools and IEC 61131-3 programming environment

D.  manufacturer specific interface between programming environment and PLC runtime

E.  CANopen tool specific interface between configuration tool and network

提示！  The figure describes not necessarily the use of different tools for programming and configuration. One tool may handle both functionality and hide the interfaces. An example is given by the programming tool CoDeSys (see dotted line), where the CANopen configuration and the runtime software on the PLC is included.

Application interface

The needs of any application from within an IEC 61131-3 level it is to read from the device object directory of a CANopen connected node or to write to it (SDO). Further elements of a CANopen communication are Process Data Objects (PDO) which are supported in the process image within the IEC application as inputs (receive PDO; i.e.: %IX.. ) or outputs (transmit PDO; i.e.: %QW.. ). Received asynchronous error messages (EMCY) are registered in a buffer for each node. The network status is controlled by the Network management (NMT). Node guarding functionality is available with CANopen as well as synchronized communication for process data.

The chapters of the current description describe the needs of a function block library for CANopen communication.