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One challenge for the designers of the current industrial control systems consists of assuring the system reconfiguration at runtime, envisaged at system design time. This article focuses specifically on the fault tolerance to controller failures (as it is the most complex challenge) aiming at redistributing the responsibilities at runtime in order to finish the current production plan. Its applicability is illustrated by means of a case study that consists of a reconfigurable control application based on the IEC 61131-3 for a flexible assembly cell. A prototype software tool guides the developer during the development process. This approach contributes to develop more flexible control systems because they can react in case of a controller failure, to increase the system availability during its operation and to reduce the production downtimes to perform the maintenance tasks. [ABSTRACT FROM AUTHOR]

This paper describes a methodology for the design and implementation of supervisors for switched-mode systems, which is a typical class of hybrid systems in industrial process applications. Many works can be found in the literature addressing formal modeling and control techniques for switched-mode systems, but they commonly deal with control design and simulation. The focus of this paper is to automate the design of supervisors for industrial switched-mode processes composed by multirate loops, in order to automatically generate the code of the supervisor. Its function is to detect changes in the process operation mode and to switch to the control algorithm accordingly. The target control equipment is the programmable logic controllers (PLCs) and, thus, the software architecture generated follows the IEC 61131-3 standard. The tool developed captures information related to the overall control system (inputs and outputs and control algorithms), as well as to the discrete dynamic of the switched-mode process from the simulation model and automatically generates the supervisor code as well as a time-driven schedule for every supervisor's mode. The improvement of the overall system performance using the switched-mode supervisor is analyzed experimentally through a performance index. [ABSTRACT FROM PUBLISHER]