Distributed control system (DCS) is a PC-based monitoring and control architecture with customized hardware and software modules which are geographically and functionally distributed throughout the entire plant/process to ensure its fail-safe functionality and at the same time capable of providing higher level of automation from raw material handling to final product shipment. DCS are dedicated for systems used in manufacturing processes that are continuous or batch oriented. Configuration and specification of a DCS depends on the requirement of a specific plant/process. In case of a DCS-based process plant automation network, DCS plays the role of the brain and nervous system. Field control station (FCS) is considered to be the main controlling unit of a DCS. FCS contains all types of I/O cards, processor cards, power supply cards, communication cards, etc. Operator station supports various types of operation and monitoring functions for smooth running of the entire DCS-based plant automation system.