he Modbus protocol, ownership of which was recently transferred from Schneider Electric to 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.
Modbus-IDA President Ken Crater said, “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 recognized fieldbus standard. According to Crater, Modbus-IDA intends to make this reformatting a priority for the organization.
"Modbus, the only industrial messaging protocol already recognized by the Internet world, has one of the largest installed bases worldwide with more than 7.2 million installed nodes,” commented Jean-Jacques Poubeau, vice-president of major programs at Schneider Electric and a Modbus-IDA board member. “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 this Industrial Ethernet solution.”