Difference Between DCS and SCADA (With Table)

The DCS is most commonly seen in industries, where it is housed in a smaller space. It makes use of a high-speed communication channel, including a local area network (LAN). DCS is process-oriented, seeing the controlled process as the center of the universe and one of its functions as data presentation to controllers.

The SCADA system is designed to span a greater geographic area. It could use a variety of communication tools, including radio and telephone. SCADA is focused on data collection: Its universe revolves around the control center and workers. The remote equipment’s sole aim is to collect data, albeit it may also do some extremely complicated process control.

Comparison Table Between DCS and SCADA

What is DCS?

A distributed control system (DCS) is an automated control system that comprises geographically dispersed control systems throughout a facility or control region. A dedicated controller controls each processing element, device, or group of units in DCS. DCS is made up of a large number of local controllers that are linked by a rising speed communication network in various portions of the plant security zone.

Data acquisition and control processes are carried out in a DCS control unit by a variety of DCS controllers, that are microprocessor-based components spread functionally and geographically throughout the facility and located near areas where controlling or data gathering duties are done. Integrated controllers can interact with each other as well as other controllers such as supervisor terminals, operators terminals, analyzers, and so on.

Field devices such as sensing devices are connected to scattered individual automatic controllers. These controllers verify that collected data is shared with other hierarchical controllers via various field connections. The connection between the controllers is established via various field bridges or conventional routing protocols. Modbus, HART,  Profibus, and arc net, are a few examples.

DCS is best suited for monitoring and controlling a huge number of ongoing controller parameters in large-scale processing or manufacturing facilities. The key benefit of separating control duties for dispersed controllers is that the plant can continue to run even if a component of the DCS fails.

What is SCADA? 

SCADA, or supervisory control and data acquisition, is a hardware and software system for monitoring and controlling industrial processes. Manufacturers can gather and analyze real-time production statistics, control and evaluate alerts, and implement automatic control reactions prompted by certain circumstances or system characteristics using a SCADA system.

System monitoring, computerized management of industrial applications and machinery, data gathering and analysis, occasion and alarm alerts, and reporting are all key capabilities of SCADA. It collects information from the sensors and other monitoring equipment, which might be digitized or analog, to accomplish these activities. The data is subsequently transferred to a remote terminal unit (RTU) or a programmable logic controller (PLC), which converts it into useful information. Finally, the data is communicated to operators via a human-machine interface (HMI) or other kinds of displays for analysis and interaction.

SCADA systems also allow for the automation of industrial operations and machinery that would otherwise have been too complicated for human operation. SCADA systems can detect unusual variables or alerts using sensors and measuring equipment and act immediately with a specified control system. Food and beverage manufacturing, Pharmaceutical,  Water/Wastewater control, and HVAC and corporate building management are just a few of the areas where Process Solutions has performed SCADA systems.

By delivering economically important data to controllers and management, a SCADA system can assist reduce production waste and enhance overall efficiency in your plant. The data obtained from a SCADA system can help you make data-driven decisions, which can result in increased output production, lower costs, and better data processing.

Main Differences Between DCS and SCADA

1. DCS is the expression for Distributed control systems, whereas SCADA is the acronym for Supervisory Control And Data Acquisition.
2. DCS is process-oriented, whereas SCADA is data-gathering-oriented.
3. DCS is a process state-driven, whereas the SCADA system is event-driven.
4. DCS systems are more integrated and capable of higher-level tasks, whereas SCADA systems are more adaptable.
5. DCS comprises one or more controllers that are utilized to apply advanced process control techniques, whereas SCADA systems are unable to do so.
6. DCS is a process control technology that links sensors, processors, operator interfaces, and actuators via a network. A DCS usually has one or more processors for control and communication using proprietary linkages and protocols, whereas SCADA stands for Human-Machine Interface (HMI). SCADA sensors are used to monitor and control chemical, physical, and technological processes.

Conclusion 

DCS and SCADA are similar as they both manage plant operations and the devices that can be deployed but on the other hand, there are many differences between them, DCS is concerned with processes, whereas SCADA is concerned with data collecting. DCS is frequently used to manage activities at a single site, whereas SCADA is chosen for purposes that span a large geographic area. DCS user workstations are always interconnected to the system’s I/O, whereas SCADA is anticipated to function even if field connections are down.

SCADA systems are focused on data collection and analysis, whereas DCS systems are focused on process control. 

SCADA systems, on the other hand, offer an advantage if you need real-time data and an open line of communication structure because their process time is quicker and they support open protocol connections.

References:

1. https://ieeexplore.ieee.org/abstract/document/6119279/
2. https://link.springer.com/chapter/10.1007/978-3-642-28920-0_7