Distributed Control System management

Distributed Control System (DCS) - A generic, microprocessor based, regulatory system for managing a system, process or facility. 

Stand-alone systems. Multiloop controllers) or programmable logic controllers (PLC) typically used to control part of a process, and larger supervisory control and data acquisition (SCADA) systems/distributed control systems (DCS) used to control the process or service as a whole (e.g., bulk primary production plant, building management systems). These self-contained systems are a component of an automated manu-... 

Control And Data Acquisition (SCADA), Industrial PC systems, and Distributed Control Systems (DCS). Measurement and control systems and process management systems are often integrated together. Process Analytical Technology (PAT) is a special case implementing nonintrusive process instrumentation. 

In 2005, he was leading a multidisciplinary engineering team responsible for the design and implementation of the Distributed Control System (DCS) of a fuUy operational pulp and paper mill with a complete paper machine in a new 11,000 m building on campus, representing a total investment of 80 million Canadian dollars, 10 % of which came directly from industry. This DCS manages over 3,000 I/Os and 500 control loops and its flexibility is still unique worldwide. 

A distributed control system may involve the use of microcomputers at the local level and the use of more powerful rruchines to coordinate overall plant control objectives. In this context, it has been suggested that process control might be described better as process management." " Local control of the operation of individual separators is still important but, with the use of distributed control, reliability is maintained (microcomputers are dedicated to particular process units) while overall technical and economic objectives are pursued (mainframe computers can perform complex on-line/off-line optimization). The advantage to distributed control is that it makes effe ve use of current technology and provides a framework within which control and optimization developments can be implemented. These developments probably will include better simulation and optimization routines that will help to assess the current state of the process plant and to suggest improvements. 

Using the distributed control system a network of control can be built up in modular fashion. Individual process control units are applied to single plant units and communicate either with each other or with a central computer via a data highway. Via the same highway, links are also available for production management information, production planning, quality control involvement, whether on- or off-line and costing operations (von Klosterlein and Vos, 1983). 

Regulatory or base layer control acts to maintain operating conditions at target values in the presence of process disturbances and it allows a smooth transition fi om one mode of operation into another, including start-up and shutdown. The base layer control (as well as the Alarm Management system) resides in a Distributed Control System (DCS). In case of Pearl GTL this is the Honeywell Experion PKS system. 

Alarm Management, DeltaV Distributed Control System, White Paper, Emerson Process Management, August 2015. 

Centralized control approach. DCS, distributed control system ESD, emergency shutdown system HMJ, human—machine interface MIS, management information system PU, pro cessing unit SIL, safety integrity level SIS, safety instrumentation system. 

Management of abnormal situations often concerns the effectiveness of the alarm system. Increased automation provides a relatively calm operating scenario when the plant is in a steady state. However, given the importance of alarms in times of upset, the display of alarm information has to be given high priority. Even if there are relatively few alarms on the system and the system is not a distributed control system (DCS) the same principles apply, to ensure a reliable response to alarms. 

Wind power A modern off-shore wind turbine dependable control-system manages up to three thousand inputs / outputs, several hundreds of functions are distributed over several hundred nodes grouped into eight subsystems interconnected with a field-bus and the distributed software contains several hundred thousand lines of code [32,33]. 

Figure 4.21 Screenshot from a Delta V distributed control system (reproduced by permission of Emerson Process Management)...

Interfacing to host systems. The receiving systems can also be equipped with host communication interfaces for cormedion to plant management systems, e.g.. Distributive Control Systems (DCS), Integrated Control Systems (ICS), oil accounting systems, etc. (Fig. T-30). Protocols have been developed in close cooperation with the well-known control system suppliers. 

FIG. T-30 interfacing to distributed control system and management information system. (Source Enraf.)... 

Control systems will play a key role in future distributed plants ]139,145]. As a rule of thumb, plants will be smaller and simpler, but the control systems will be much more advanced, of a standard not known today. Plant personnel for operation and managing will ultimately no longer be required, except for start-up, shutdown, and services. This is a shift from a regulatory to a servo role, supported by a sophisticated sequence control. Control is needed for safety issues, operability, and product quality control. Sensors have a central role to provide the information needed for control and modeling and simulation is needed for process models. 

The distribution of quality management system documentation is controlled. The documented quality management system gives due consideration to the following elements ... 

The entire system is based on a tiered approach where three layers of technology are integrated into the overall treatment system, as illustrated in Chart 2. First, a distributed process control system is network linked to the various component subunits of the waste management system such as pH control, ion-exchange control, tank level control, etc. Next, are the recovery/treatment processes themselves. The final tier is a monitoring system which controls both the performance of the treatment systems and the discharge assurance of the plant effluent... 

The Use of Artificial Intelligence in Distributed Control Model Based Reasoning Approach to Chemical Plant Design Use of Expert Systems in Nuclear Power Plants Application of AI to Management and Analysis Problems... 

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