During the deployment of industry automation got two trends as a crucial importance. The complexity of control tasks increases permanently and the reusability of software components was more and more mandatory. New adequate technologies were developed in the field of commercial communication. The basic concepts are, firstly, introduction of a component based software architecture. That means all software components in a system (visualize systems, control tasks, sensor/actuator driver) are build according to a component model that is standardized and independent from manufacturers and platforms. Secondly, the concept is the use of an extended system software layer, called ‘middleware’. A middleware is the extraction of manufacturer and platform independent functions and service of control tasks, to enable a seamless integration of diverse distributed applications across different heterogeneous platforms. So, middleware is the consequent further development of a network operating system. Middleware integrates all necessary operating system, network function, communication and additional services and provides as API (Application Programming Interface). In the following typical services of a middleware system for industry automation as below:
• Connection with QOS
Function: data connection between one or more components with guaranteed transmission parameters.
• Global time base
Function: absolute time base of synchronous in all network stations. Synchronous clocks with for instance a maximum delay of 100us.
• Component management
Function: activation, de-activation, status logging, search.
• Event handling
Function: Soft, interrupt function. Fast event signaling.
Function: consistent process of operation over multiple components.
Function: the access regulation to the components and resources in a system for instance data security, authentication.
It is possible to unify technical and user requirements in the engineering field, programming, industrial decentralization and cross linking with over networks. However, different requirements of different application fields to the development of different middleware software standards from different manufacturers. On the one hand there are communication orientated middleware systems, consisting an abstraction of network programming such as Web service, Java RMI.