Bullet Sensors & Transducers e-Digest, Vol. 54, Issue 4, April 2005: Product News

    (ISSN 1726- 5479)


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Modbus-IDA and CAN in Automation Announce CiA DSP 309:

Interfacing CANopen with TCP/IP Part 2: Modbus/TCP Mapping



Modbus-IDA and CAN in Automation e.V. (CiA) have announced a licensing agreement, resulting in Specification CiA DSP 309-2: Interfacing CANopen with TCP/IP Part 2: Modbus/TCP Mapping. CiA DSP 309-2 provides a standardized mapping of CANopen data for transport on Modbus TCP networks. In the specification, Modbus Function Code 43/13 is reserved for this purpose. The reservation of this function code exclusively for CANopen is simultaneously being submitted to the Modbus-IDA RFC standardization process.


CiA will maintain the specification, which will be available for CiA members on the CiA website (http://www.can-cia.org) and for Modbus-IDA members upon request (headquarters@can-cia.org). The specification defines mapping services so that CANopen devices can communicate over a Modbus TCP network via a gateway device or through the incorporation of a local Modbus TCP transport layer. Access to the entries of a CANopen object dictionary is supported on both a read and write basis, along with a variety of device control functions. 


For users, this specification increases the options for communicating via Modbus TCP by standardizing the way Modbus communications will be used with CANopen. This also decreases the opportunity for multiple incompatible approaches proliferating. Modbus-IDA President Ken Crater commented, “We are delighted to see this extension of capability being promulgated by the CAN in Automation group, and believe the result will be to better serve suppliers and users. In keeping with the commitment to open, accessible protocols, our two organizations seek to harmonizeour efforts with the publication of this specification, rather than attempting development along parallel incompatible paths.”





Monika Mack,

CAN in Automation (CiA)

Am Weichselgarten 26

DE-91058 Erlangen,

Tel.: +49-9131-69086-0

Fax: +49-9131-69086-79

E-mail: headquarters@can-cia.org





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