connection technology continue to simplify the design and wiring that go into industrial control panels. E ver since the first control panels were installed on the floor of industrial plants, there have been attempts to reduce the amount of wiring and effort that goes into connecting industrial processes and machines to their controls. Decades ago, programmable logic controllers (PLCs) began re...

In this paper, we present a proposal to implement the IEC 61131-3 software model. This model establishes the high-level elements of the Programmable Logic Controllers. We discuss some of the points of the standard that should be clariWed before implementing it, such as concurrency, variable scope and cyclic operation. We show the implementation guidelines using POSIX compliant Real-Time Operati...

In this work a three-level control system for the vacuum-plasma system with the ion source based on high-frequency induction discharge architecture is described. The system is built on smart sensors and specially designed for operation in high EMI programmable logic controllers (PLCs) in the middle hierarchical level. The structure of PLC and the algorithms of the system are presented. Results ...

Sequential function charts (SFC) are a high-level graphical programming language for programmable logic controllers. Their main purpose is to provide a structure and organization of the control flow. Therefore, various features such as parallelism, priorities on branching transitions, and activity manipulations are incorporated. The syntactic rules for building SFCs are formally defined in IEC ...

Programmable Logic Controllers (PLC) are frequently used in the automation industry for the control of hybrid systems. Although the programming languages for PLCs are given in the standard IEC 61131-3, their semantics are defined in an ambiguous and incomplete way. This holds in particular for the graphical language Sequential Function Charts (SFC), a high-level programming language comprising ...

The goal of this article is to present our remote laboratory as a means of distant-programming environment which provides remote users for the possibility to use control systems, widely employed in industrial applications. The lab is aimed towards people from universities as well as from industrial companies, and comprises two models based on pneumatic and electromagnetic principles and control...

This paper describes a method for model-based development of software for programmable logic controllers (PLC). The method includes modeling of a control algorithm, verifying the algorithm with respect to the requirements, and automatically generating the code in one of the IEC 61131 languages. The modeling language is UML state machine diagram, and the verification tool is UPPAAL model-checkin...

Programmable Logic Controllers (PLCs) are playing an increasing role in the construction of safety critical systems. The standard IEC 1131-3 deenes a number of interrelated languages for the expression of PLC programs. Here we consider a subset of the IEC 1131-3 languages, that of function blocks, and present an assessment of the standard from the viewpoint of providing a formal semantics to th...

The tool Moby/RT supports the design of real-time systems at the levels of requirements, design specifications and programs. Requirements are expressed by constraint diagrams [Kleuker, 2000], design specifications by PLC-Automata [Dierks, 2000], and programs by Structured Text, a programming language dedicated for programmable logic controllers (PLCs), or by programs for LEGO Mindstorm robots. ...

SIL's (Safety Integrity Levels) are used by IEC 61508:1998 [1] to characterise the required functional safety of computer control systems. For example, SIL 4, the highest rating is for fly by wire aircraft and weapons systems and track circuited train signalling systems while SIL 2 is typical of certain Programmable Logic Controllers (PLC). Fire control panels have not been SIL rated to date ev...