The Technological Concept of IDA

Distributed Intelligence is based on communication through Ethernet TCP/IP. The middleware used by IDA for real-time communication is based on the UDP/IP belonging to TCP/IP, and provides services supplying unambiguous device names, functions and variables system-wide. Above that, the middleware is responsible for synchronising the distributed applications, as well as monitoring communication timing. Intelligent devices are exchanging data during run-time by sending them to the middleware, and by receiving data from it.

The middleware is responsible for all required converting of data. Communication is based on the Publisher/Subscriber Model which significantly simplifies programming communication between one sender and various receivers, and which greatly minimises the network load. Another advantage of this model is the fast and efficient communication, as no polling is required. Thus, event-driven data transfer without undesired enquiry telegrams is possible.

 

Web-based communication is based on TCP/IP. With the help of standardised Internet protocols like HTTP, FTP or SNMP, data are exchanged for programming, parameterising, troubleshooting and operation of devices and production plants. The IDA object model is located above these communication levels. Here, objects are managed which are required for the process image, for parameterising, event-handling, for loading programs and for troubleshooting.

Through a standardised program interface, applications like engineering tools or application programs have access to the data stored in the object model. Due to system management, simple plug & play for commissioning and maintenance is possible in IDA-compatible devices. Thus, an automated network is achieved with defined behaviour regarding the assignment of IP addresses and device names. The system diagnostics is greatly improved by the topological display of the network and creation of hierarchical lists of all network participants, so that in the case of faults there will be only minimum down-times.

 

IDA and Ethernet in Automation Organisation IAONA Europe e.V. have made an agreement regarding their cooperation. The objective is to develop joint standards which will make it possible to use varying Ethernet solutions in one network. The overall goal is to offer to the user compatible systems for automation technology, based on the Ethernet - including those which do not meet the IDA Standard.

 

IDA and the Modbus TCP/IP

Modbus TCP/IP is the most popular industrial Ethernet protocol in automation technology worldwide. The IDA Group has decided to closely co-operate with the Modbus user group, and is adopting Modbus into their IDA Standard as quasi standard for Ethernet communication in automation technology. Modbus TCP/IP has been submitted to the IETF (Internet Engineering Task Force) in order to establish the protocol as official Internet standard. Thus, Modbus TCP/IP will be implemented as standard into all major operating systems, such as FTP or HTTP. Apart from that, Modbus occupies one of the first 1000 dedicated ports, namely port no. 502. The fact that this port is no longer available for other applications is another factor which helps to establish Modbus as standard. Modbus TCP/IP will become part of the IDA standard which leads to a situation where a large installed basis and several hundred manufacturers will be available for it. As Modbus TCP/IP is completely transparent, it perfectly fits into the IDA strategy of open standards. IDA will actively support the work group activities of the Modbus organisation, and contribute to the development of tool kits.