Standardised access to CANopen services from IEC 61131.

CAN in Automation (CiA) has released the CiA 314 specification, which substitutes partly the CiA 405 specification published around 20 years ago.

Function block for creating object

dictionary entries

The other parts of CiA 405 have been moved already some years ago to the CiA 302-4 (network variable and process image) and the CiA 306-3 (electronic datasheet) documents. The CiA 314 document specifies CANopen-specific function blocks, e.g. to write or to read SDOs (service data objects), to inquire the NMT (network management) state or the CANopen kernel state.

Other function blocks are dedicated for transmitting and receiving EMCY information (emergency messages) as well as for creating object dictionary entries. The providers of CANopen devices programmable in IEC 61131-3 languages and related Soft-PLCs may implement these function blocks to make the application software portable to other platforms. This increases the re-usability of application programs.

CANopen devices programmable in IEC 61131-3 languages are used in factory automation, machine control systems, “intelligent” drives as well as displays, and increasingly in mobile machines.