Industrial Control

Abstract: This contribution seeks to identify the short and long-term economic and cultural effects of file sharing on music, films and games, while taking into account the legal context and policy developments. The short-term implications examined concern direct costs and ...

Distributed Real-time Embedded (DRE) systems are increasingly used in critical domains such as avionics, vehicle and industrial control as well as in medical systems. They must be designed carefully and have to provide safety properties because a failure could mean loss of life. For these reasons, it is recommended to automatically generate a significant part of the code from the models describing the critical aspects. In our approach, we automatically generate two kinds of code from architectural models. The first one plugs the user functional code in the middleware, the second one provides a significant part of the middleware functions. Both rely on a hand coded written middleware that provides the minimal facilities to plug the generated code and to resolve portability issues. In this paper, we present our code generator and the middleware designed to generate High Integrity (HI) systems. We demonstrate via several use-cases how we succeeded in meeting the requirements of DRE sys...

A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.

Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.

The design engineers need to use high level formalisms to facilitate the development, maintenance, and documentation of the industrial control systems. These formalisms must permit the modeling, formal validation, and code generation to PLC. This paper discusses statechart for modeling of industrial systems, and presents a case study that simulates the general schema of the industrial automation process, based in PLC. The case study was implemented with Java technologies, and was simulated using the execution environment developed by the Jakarta Project Commons SCXML.

The Grafcet (or sequential function charts) language is a graphic language often offered in programmable logic control systems (PLC) used for industrial control-command applications. Modeling of Grafcet by the synchronous data-flow language Signal gives both explicit semantics, and the corresponding simulator. The translation into a graph of tasks makes it possible to execute the Grafcet program on any hardware architecture. Moreover, the use of Signal's proof tools allows verification of Grafcet properties, opening the field of critical applications to this very expressive language

Supervisory control and data acquisition (SCADA) systems are widely used in industrial control and automation. Modern SCADA protocols often employ TCP/IP to transport sensor data and control signals. Meanwhile, corporate IT infrastructures are interconnecting with ...