How to can talk about SCADA and DCS Systems in 3 Easy Steps: include a friendly Guide about Control Levels

Again, I wanted to talk about a different topic than what I had planned to write about. My idea was to talk about cybersecurity in OT and IT environments, not in the depth that a specialist could provide, but with enough clarity for people interested in creating or improving their control center. But after a call with a friend, she asked me about something that many people have explained in various articles and documents, but few times do they reach our hands: the difference or the real difference between a DCS system and a distributed SCADA system.

First, let's define each one:

DCS System (Distributed Control System): A DCS system, or Distributed Control System, is a control and monitoring platform used in various industrial environments to centrally supervise and control the processes and operations of a plant or facility. A DCS system consists of multiple distributed equipment that communicate with each other to collect data, perform actions, and provide real-time information to operators. These systems are highly scalable and allow for the control of multiple devices and processes simultaneously.

SCADA System (Supervisory Control and Data Acquisition): A SCADA system, or Supervisory Control and Data Acquisition system, is a software and hardware platform used to monitor and control processes and operations in real-time. A SCADA system collects data from sensors and devices in a centralized control system, allowing operators to monitor and control processes remotely. Additionally, SCADA systems can also perform data analysis, generate reports, and send alarms in case of abnormal conditions or emergency situations. SCADA systems are commonly used in industries such as energy, water, manufacturing, and transportation.

My response to her was that a DCS system is typically used to monitor industrial systems (automations) and, unlike a SCADA system, it is specialized in data collection and responds to a 3-level control architecture (although over the years, new levels have been incorporated). The N1, N2, and N3 control architecture refers to a classification used in SCADA systems to describe the distribution of control and monitoring components. This classification was developed by Honeywell in the 1980s.

N1 (Level 1): Also known as the plant level or control level, it is the lowest level of the SCADA architecture. This is where field devices and sensors that collect process data such as temperature, pressure, and flow are located. These data are transmitted through process controllers or remote terminal units (RTUs) to higher levels for processing.

N2 (Level 2): Also called the supervision level, it is the intermediate level of the SCADA architecture. This is where the SCADA server is located, which receives data from the N1 level and processes it for visualization and control. The SCADA server stores the data in a database and provides a graphical interface for operators to monitor and control the process.

N3 (Level 3): Also known as the management or enterprise level, it is the highest level of the SCADA architecture. This is where management and planning systems that use data collected by the SCADA system for strategic decision-making are located. This level is connected to other enterprise systems, such as human resources management systems or production planning systems.

It is important to note that this level classification may vary depending on the provider and specific implementation of a SCADA system. Honeywell pioneered the development of the N1, N2, and N3 control architecture, but nowadays there are other SCADA system providers that use similar or customized architectures to meet the specific needs of each industry.

Now we must understand that each system is "special" or specialized for the field in which it was created, and that often being its creator does not necessarily mean being its leader or having the best product.

1. Electrical SCADA: These systems are used in the electrical industry to supervise and control processes related to the generation, transmission, and distribution of electrical energy. They allow monitoring and control of substations, transformers, transmission lines, generators, and other electrical equipment. Electrical SCADA systems can also help manage load, detect faults, and optimize energy efficiency.

2. Process SCADA: These systems are used in various industries such as chemical, petrochemical, food, and pharmaceutical industries to supervise and control production processes. They allow real-time monitoring and control of variables such as temperature, pressure, flow, and product quality. Process SCADA systems can also generate reports, perform data analysis, and send alarms in case of abnormal conditions or risk situations.

3. Water and Wastewater SCADA: These systems are used to supervise and control operations related to water supply, wastewater treatment, irrigation, and other water-related processes.

4. Transportation and Traffic SCADA: These systems are used to monitor and control traffic on roads, bridges, tunnels, and public transportation systems. They enable efficient traffic management, incident detection, and optimization of vehicle flows.

5. Oil and Gas SCADA: These systems are used in the oil and gas industry to supervise and control operations on offshore platforms, refineries, pipelines, and gas pipelines. They help ensure safety, quality control, and process efficiency.

6. Smart Building SCADA: These systems are used in commercial and residential buildings to supervise and control HVAC systems, lighting, security, energy management, and other aspects related to building efficiency and comfort.

7. Manufacturing SCADA: These systems are used in the manufacturing industry to supervise and control production processes, inventory management, product quality, and other aspects related to plant efficiency and performance.

Therefore, we must understand that DCS may be more recommended in applications where centralized control and distributed monitoring of complex processes in industrial environments are required. Some of the areas where the DCS system is commonly used include:

- Chemical and petrochemical industry: The DCS system is widely used in the chemical and petrochemical industry for process control, handling of hazardous materials, and safety management.

- Food and beverage industry: In food and beverage production, the DCS system is used to control mixing, heating, cooling, fermentation, and packaging processes to ensure production quality and efficiency.

- Pharmaceutical industry: In the pharmaceutical industry, the DCS system is used for control of drug manufacturing processes, ensuring precision and safety in production.

- Manufacturing industry: In manufacturing, the DCS system is used for control of automated production lines, quality monitoring, inventory management, and maintenance control.

Given that call centers (data collection systems can be closer to the source), they are recommended in applications where real-time monitoring and process control are required, especially in the following cases:

Electrical grid management: Spectrum Power is a SCADA system with references in the management of electrical grids. It is used in the electric industry for real-time monitoring and control of substations, energy distribution, load control, event management, and data analysis.

Oil and gas industry: SCADA systems are used in the oil and gas industry to monitor and control production, transportation, and distribution processes. They allow monitoring of pressure, temperature, gas and oil flow, as well as detecting and responding to abnormal events or emergency situations.

Water management and wastewater treatment: They are used in applications related to water supply and wastewater treatment. They enable monitoring and control of water flow, tank levels, water quality, pump and valve operation, and real-time analysis to optimize the treatment process.

In summary, SCADA systems are recommended in applications that require real-time monitoring and control of specific processes, such as electrical grid management, the oil and gas industry, water treatment, and manufacturing industry. The choice of the SCADA system will depend on the specific needs and requirements of each application.