IEC accepts Modbus protocol as a PAS

The Modbus protocol, whose ownership was transferred from Schneider Automation to Modbus-IDA, has been accepted by the IEC as a Publicly Available Specification (PAS).
The ubiquitous Modbus protocol, whose ownership was recently transferred from Schneider Automation to an independent nonprofit organization, Modbus-IDA, has been accepted by the IEC as a Publicly Available Specification (PAS). The TCP variant of the protocol, along with a companion protocol known as RTPS, were submitted to IEC SC65C as a real time industrial Ethernet suite. The submission was made possible by the recent granting of a type D liaison status to Modbus-IDA by the IEC.

Of 25 countries voting on the proposal, there was only one negative vote, reflecting overwhelming approval of the specification.

At the same time, the specification was accepted as a New Work Item by the subcommittee.

Modbus-IDA President Ken Crater stated, 'We are delighted to be the first PAS to be approved during this submittal period.

Although our organization is quite new, this approval reflects the outstanding acceptance that Modbus has received in the industrial marketplace over the past 25 years.

More significantly, however, this Publicly Available Specification represents our organization's dedication to bringing a new level of openness to industrial communications.' In approving the document, several national committees asked for a reformatting of the specification to allow for better integration into the revision of IEC-61158 (Ed 4.0 2007), the well-known fieldbus standard.

According to Crater, Modbus-IDA intends to make this reformatting a priority for the organization.

Jean-Jacques Poubeau, VP of Major Programs at Schneider Electric and a Modbus-IDA board member, also commented: 'MODBUS, the only industrial messaging protocol already recognized by the Internet world (port 502) has one of the largest installed bases worldwide with more than 7.2 million installed nodes.

With this positive vote, the MODBUS TCP-IP profile has been accepted by the IEC as a Publicly Available Specification and is now eligible to become part of future editions of the International Standards IEC 61158 and IEC 61784-2.

This is a significant step forward for the efficient, proven and cost effective Industrial Ethernet solution supported by Schneider Electric.' The agreement transferring the modbus protocol to Modbus-IDA was signed by Schneider Automation on April 12, 2004 and was publicly announced that month at the Hanover Fair trade show in Germany.