Control room re-instrumentation: "online"

Re-instrumentation of existing process control rooms can be undertaken in a variety of different ways, all of which fall into one of two strategies: off-line approach, e.g., during a plant shutdown; or online approach with process plant fully operational. This paper discusses the pro's and con's of both methods before outlining the advantages of online change-over and problems which need to be addressed to ensure a safe and successful change-over, with the minimum disruption to production.