Using Synchronous Language For Signalling

Abstract

Today, Signalling engineers must no longer merely program, but also specify, validate and implement, to attain the end goal of a proven fault-free system. With the revolution in microprocessing power, designers of critical real time systems have experienced a gradual evolution in this field. Most of these designers have been forced to abandon their traditional way of thinking, a product of their electronics engineering culture, and to take on the culture of software engineers, who first believed they would come up with miracle tools and languages. The problem, of course, is that the programming languages proposed were not appropriate to the needs of signalling engineers. In particular, the sequential concept was not appropriate for the parallel structure intrinsic to the problems in question. Synchronous Data Flow languages could provide a satisfactory solution for designers of critical real time signalling systems. The data flow model is, in fact, directly based on a description in the form of block diagrams preferred by automation engineers. Moreover, the synchronous model perfectly matches the execution mode of the systems described in terms of input sampling, calculation, output transmission and return in an infinite loop.