IDA elects new board, announces technology developments

Seligenstadt, Germany - Schneider Electric's increasing visibility in the IDA organisation (Interface for Distributed Automation) became apparent at the recent membership meeting hosted at Schneider's German headquarters. Two new Schneider representatives were elected to the board and an announcement was made that the group would include the Modbus TCP/IP protocol in its IDA stack.

By Control Engineering Staff July 29, 2002

Modbus takes its place in the IDA stack, next to NDDS.

Seligenstadt, Germany – Schneider Electric’s increasing visibility in the IDA organisation (Interface for Distributed Automation) became apparent at the recent membership meeting hosted at Schneider’s German headquarters. Two new Schneider representatives were elected to the board and an announcement was made that the group would include the Modbus TCP/IP protocol in its IDA stack.

The governing board has been re-arranged, with Martin Jetter (Jetter AG) as the new chairman and Martin Müller (Phoenix Contact) as the treasurer. Volker Arlt from Lenze was elected to the board as well as two members from Schneider Electric to replace Dr. Schoop: Diego Areces (marketing) and Manfred Brill (chairman, technical steering committee).

Founded in 2000 by companies such as Lenze, Jetter, Phoenix Contact, Schneider Electric, SICK, and Turck, the IDA group is proposing standards for real time distributed automation based on Ethernet and Web technologies.

Modbus TCP/IP

Noting that Modbus TCP/IP is “already a quasi standard” for Ethernet communication in automation technology, the board said it would bring Modbus into the IDA stack and support the activities of the Modbus organisation.

“Strategically, two things are achieved by integrating Modbus into the IDA stack,” he said. “First, Modbus meets the lowest IDA conformity level, and has the option for other upward compatible services based on the client/server and the publisher/subscriber model. Secondly, due to its lean protocol and the lean Schneider TCP/IP stack, IDA will be available for implementation in very low level devices.”

Schneider Electric says it will have first prototypes of a Modbus chip with integrated TCP/IP early next year.

However, Modbus will not replace RTI’s NDDS, which will continue to be used for real time applications. IDA is taking advantage of the fact that different protocols can co-exist in an Ethernet system. “There can be parallel communication paths,” explains Mr. Buchwitz. “We can have NDDS running, which follows the publisher/subscriber model, a client/server application, and Modbus TCP/IP all running at the same time.

“We’re not using Modbus for real time communications, we’re using it because it’s a widely accepted standard. We are, in effect, broadening the IDA concept; we’re opening it up horizontally.”

As an example of the parallel communications concept, intelligent devices such as PLCs or drives will communicate via NDDS while at the same time, on the same system, an I/O module communicates its status to another device or into the global database via Modbus. The IDA group envisions its networks as including both “smart” devices and basic sensor and actuator devices.

Control Engineering Daily News DeskMichael Babb, editor, Control Engineering Europe michael.babb@cahnerseurope.com