Quality assurance system for the distributed control system project

Abstract

This research is to study the application software development of the distributed control system (DCS) in a manufacturing company named ABC (unreal name). The company delivered a DCS product including both hardware and software. Since the hardware is manufactured aboard, this research focuses only at the software development from the process of gathering the customer requirements to the software inspection test and product delivery. The developed application software is made-to-order and unique. The company provides different software according to the different needs of different customers. The writer has used the failure mode and effect analysis (FMEA) and the fault tree analysis (FTA) as quality tools for analysing the potential failure modes and their effects in the DCS project execution in a systematic way. From the study, the writer has discovered three major problems in the DCS project execution. These included (1) lack of procedures to control the project execution, (2) lack of the document and data control, and (3) technical problems. The result of these problems heavily affects to the DCS project execution. The company is unable to deliver the DCS to the customer on time for several projects and software bugs are also embedded to the delivered software product. These lead to the customer dissatisfaction and the company itself has made the profit much less than it was expected. The results of the analysis using the FMEA technique have leaded to the establishment of the quality assurance system for the DCS project execution which include checklists, standard document and prodedures, and the engineering database pool software (EDP). The EDP retains the useful engineering knowledge and the application software functions of the past DCS projects. The EDP is developed with the purpose to share and enhance engineering knowledge of engineers and to reuse the past application software functions so that engineers do not have to redesign the customer requested functions which have already been created before. The established quality assurance system has been implemented to one DCS project in the company and the results were the improvement in software quality and on-time delivery. 37 software errors were detected during the pre-inspection test and there were only 8 errors during the inspection test with the customer, comparing to the average of 50 to 60 errors found during the inspection test in the past projects. In the view of changes in RPN (Risk Priority Number), the percentage of RPN for each critical process of the project execution comparing between before and after implementation decreased 33 to 94%.