Based on a general design model for distributed control systems, and using standardised languages of IEC 1131-3 for control, three approaches to programming are investigated. The first is based on IEC programs with ex...
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Based on a general design model for distributed control systems, and using standardised languages of IEC 1131-3 for control, three approaches to programming are investigated. The first is based on IEC programs with extensions, the second is a decomposition of programs with SFC notations and the third approach uses function blocks corresponding to the IEC TC65 Function Block Standard. The approaches are specified and compared, and conclusions for their use and for further work are drawn. The intention of the contribution is to discuss possibilities for open programming models, rather than to present final results.
In three cases in the Canadian nuclear industry, computerized versions of control systems encountered serious problems where similar hardwired systems had previously been completely successful. Study of these aberrati...
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In three cases in the Canadian nuclear industry, computerized versions of control systems encountered serious problems where similar hardwired systems had previously been completely successful. Study of these aberrations makes it possible to discern the underlying causes, which lie almost entirely in the realm of system design but are aggravated by deficiencies in conventional software practices. Remedial changes in procedure and technology are proposed
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