Industrial Control Systems - Legacy System Documentation and Augmentation

Industrial control systems are used to automate process industries. Over 50 billion USD worth such systems are more than 20 years old resulting in their hardware having become outdated. Yet the process remains very little altered. These legacy systems need to be migrated to newer hardware and software platforms to ensure support and compliance to current standards. The time elapsed has resulted in shortage of subject matter and system experts available to understand the nitty gritties of the process functionality implementation in the legacy system using control language of that era. Documentation, if at all existing, is as built and not as running. Hence there is a need to generate documentation that could be understood by current generation automation and process engineers from the back-up of the running legacy system. This paper proposes a novel software tool to generate documents from the legacy industrial control system back-up. We test it with a real legacy system and verify the documents with actual back up. This helps in brownfield engineering migration projects.