V. Dubinin Russia, Penza, Penza State University Implementation of Some Kinds of Interactions and Communications in Iec 61499 Architecture

In this paper some kinds of interactions and communications in IEC 61499-based systems and the ways of their implementation on the basis of function blocks are presented. Examples of binary semaphores, " producer-consumer " problem and distributed data management system implementations are considered. Besides, the function block-based implementation of interpreted Petri nets, on the basis of which many various kinds of interactions in control systems can be in turn implemented, is submitted. Function blocks of new emerged international standard IEC 61499 are intended to be used as a method of development and implementation of distributed industrial-process measurement and control systems [1]. The features of function block model (FBM) are an event-driven state machine with data path (called Execution Control Chart-ECC), event input and output variables (EI-and EO-variables) with own controls, input and output variables for representation of dataflow, and also orientation of function blocks to implementation. The sampling of input and output variables values is made by means of corresponding event input and event output. For this purpose the special WITH-qualifier is used. According to IEC 61499 an application is represented as a network of the function blocks interconnected via data and events. The function blocks can run on various devices and resources of a system. All devices in the system are connected by means of a communication network. All kinds of interactions in concurrent processes systems are reduced to two basic kinds: sharing the resources and message passing. To organize each of these two types of interactions in each of computation model and language, their own synchronization tools are used. For example, language constructs such as semaphores [5], monitors, mutual exclusion belong to the first group of the methods. The message passing approach is characterized by the rendezvous in Ada, channels in CSP, which OCCAM is an implementation of, and the send-receive constructs in PLITS. Both groups of the methods are equivalent in their power. It is reasonable to implement some synchronization methods as function block systems. For example, the simple reason that exhibits convenience of implementation of semaphores in IEC 61499 architecture is presence of finished decisions (derived by their use) of many synchronization problems, including mutual exclusion, "producer-consumer", "reader-writer", etc. However, all the variety of interactions in the distributed systems in general is not reduced only to synchronization problems. The important part of interactions is inter-modular (inter-node) communications. Usually they take shape of communication protocols. In IEC …