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DCS (Distributed Control System) is a control system in which the components that make up the system are distributed geographically and functionally around the process areas. The main function of the DCS is to receive inputs from field mounted instruments (Flow, Pressure, Level, Temperature, Analysis etc), process the information in a predetermined program and provide control signal to final control elements, generate reports etc.

Thus DCS is a control system which collects the data from the field and decides what to do with them. Data from the field can either be stored for future reference, used for simple process control, use in conjunction with data from another part of the plant for advanced control strategies.


What must be in the DCS for it to be able to do so much?

Operator Console
These are like the monitors of our computers. They provide us with the feedback of what they are doing in the plant as well as the command we issue to the control system. These are also the places where operators issue commands to the field instruments.

Engineering Station
These are stations for engineers to configure the system and also to implement control algorithms.

History Module
This is like the harddisk of our PCs. They store the configurations of the DCS as well as the configurations of all the points in the plant. They also store the graphic files that are shown in the console and in most systems these days they are able to store some plant operating data.

Data Historian
These are usually extra pieces of software that are dedicated to store process variables, set points and output values. They are usually of higher scanning rates than that available in the history module.

Control Modules
These are like the brains of the DCS. Specially customized blocks are found here. These are customized to do control functions like PID control, ratio control, simple arithmetic and dynamic compensation. These days, advanced control features can also be found in them.

These manage the input and output of the DCS. Input and output can be digital or analogues. Digital I/Os are those like on/off, start/stop signals. Most of the process measurements and controller outputs are considered analogue. These are the points where the field instruments are hard-wired to.

All above mentioned elements are connected by using a network, nowadays very often used is Ethernet.

The practical and technological boundaries between a Distributed Control System DCS, Programmable Logic Controller PLC and Personal Computer PC control are blurring. Systems traditionally associated with process control are being used in discrete applications. Likewise, traditionally discrete solutions are used increasingly in both batch and continuous process control.

Today's control hardware are constructed from many of the same standard industry components such as Intel processors. Therefore the only real difference between control systems is at the software level.


ABB / Industrial IT - Advant Master DCS

Advant OCS (Open Control System) is an ABB solution for operators to improve their manufacturing productivity and achieve sustainable competitive advantages.

In 1992, based on the success of the Master systems in the 80's, the Master system began its evolution to Advant OCS. This evolution introduced high capacity controllers and I/O with an improved redundancy scheme. Also included were modern UNIX workstations, and in 1996 S800 I/O was added providing modular flexible remote I/O.

In 2000, Advant OCS with Master Software began its next step in the evolution process with the introduction of Industrial IT enabled products. ABB's commitment to protecting your investment continues with these enhancements by providing connectivity to our latest control offering.

A versatile and complete range of process I/O systems within the Advant family enables optimal user configurations:

S100I/O - A rack-based I/O system for AC400 controllers S600I/O - A rack-based I/O system for AC100 controllers S800I/O - A highly modularized and flexible I/O-system

Numerous characteristics and functions facilitate and improve operation, monitoring, and reengineering of each process in a company. 800xA Operations (Process Portal) and the proven AdvaCommand for Unix solution (based on HP-UX) are available as an operator station for Advant OCS with Master Software.

The intuitive operator software provides consistent access and interaction with data from multiple control and I/O to plant and enterprise information.

ABB Advant Master Control Systems


Honeywell Experion™ Process Knowledge System (PKS)

Experion is Honeywell's unified system for process, business, and asset management that helps industrial manufacturers increase their profitability and productivity.

Experion takes customers well beyond Distributed Control System (DCS) functionality with an advanced automation platform solution and innovative application integration to improve business performance and peace of mind. And there's no need to worry about upgrading from TDC 2000®/TDC 3000® or TotalPlant® Solution (TPS).

The unique, patent pending design of Series C combines sleek styling and function to provide process I/O with reduced footprint, easier installation and maintenance, and longer life. The Series C form factor benefits extend to multiple modules, such as the Series C C300 Controller, the Fieldbus Interface Module, the Control Firewall, and HART analog modules.

The Control Execution Environment (CEE) is the common core software used in the various controllers supported by ExperionTM. This includes the C200 Process Controller, the C300 Process Controller, the Application Control Environment (ACE) and the C200 Simulation Environment (SIM-C200). The CEE provides an execution and scheduling environment where control strategies are configured from a rich set of standard and optional function blocks using a single builder tool, Control Builder.

Function blocks are grouped and wired together in a container to perform a specific control function such as a valve control strategy. The Control Execution Environment (CEE) supports two types of containers: the Control Module in which continuous and discrete controls are combined; and an SCM, which is used for sequence control. Function blocks support the complete control application range, such as continuous, discrete and batch control.

Honeywell - Experion PKS


Emerson Process Management / DeltaV

DeltaV is the creation of Emerson Process Management's technological innovators, who worked in an off-site "out-of-the-box" think tank to build an automation system that could integrate and leverage today's digital world and cutting-edge technological innovations to make a value step-change in the process industries.

The name DeltaV is derived from the engineering equation for acceleration: dv/dt, the change in velocity over the change in time. The DeltaV system makes planning, engineering, installing, commissioning, training, operating, and maintaining your process EASY, which accelerates your success in improving your plant performance.

The DeltaV system scales the complete range of applications from an isolated process area to a complete plant-wide automation system. Whether you need tens of I/O or tens of thousands of I/O-any size you want! The DeltaV system provides all the tools to manage your process easier than ever before.

The complete family of controllers is available to power your most advanced control strategies. Full controller and power supply redundancy is available for your mission-critical applications. The controller and I/O sub-system is rated for Class I, Division 2 and Zone 2 environments to reduce your installation costs.

DeltaV workstations are based on the latest Intel-based microprocessors running the Microsoft Windows XP /Windows 2003 operating system. A complete range of applications is provided to cover system configuration, operator interface, engineering, maintenance, and integration functions.

The DeltaV control network—a high-speed Ethernet LAN—provides system communications and connects the various system nodes. The control network can be fully redundant. DeltaV remote services extend the operations, engineering, and diagnostic applications across your enterprise network.

Unlike PLC/HMI solutions, the completely integrated DeltaV system features a single database that coordinates all configuration activities. System configuration is globally distributed in the run-time environment.

Emerson - DeltaV
Hybrid Systems