Modelo para determinação do tempo ótimo de substituição de controladores lógico programáveis

Abstract

This research study will use the installed basis of Programming Logic Controllers (PLCs) at Coke Plant and the historical data base (through SISMANA maintenance system and through the experience/memory of the maintenance staff), as well as the possibility of developing accelerated life testing aiming at realizing the life data analysis (LDA) and the life-cycle cost analysis (LCC) of the PLCs. Data will be collected through research at SISMANA, interview with the maintenance staff and will be treated with the reliability software (Reliasoft Synthesis) and electronic spreadsheet software (MS – Excel). The stages of the study will be as follows: preparation for the sample collection, realization of the research, treating of the sample (critical analysis of the information obtained), interview with the maintenance staff, registering and analysis of the data, research and analysis of viability of accelerated life testing, treating of the data, calculation and modeling of failure distribution functions, calculations of costs, payback, IRR (internal rate of return) and NPV (net present value), definition of optimal model, and conclusion. The study will comprehend the PLCs installed at the Coke Plant, including its sub-areas: Coke batteries, Coke Dry Quencher Unities, Coke handling area, coal handling area, coal Yard and Gas treatment area. The main obstacles for the accomplishment of the study are the quantity and quality of the available information, the availability of the maintenance staff, and the acquisition of the software (Reliasoft Synthesis). The ultimate goal of the study is to determine a robust model, containing quantitative and statistical information, in order to support the Board of Directors to make decisions as to the application of the sources of investment. It is desirable that investments be applied at the most adequate moment as for the technical, risk and financial management approaches.