2417

Knowledge Base: What is SCADA? How Does it Work?

What does SCADA stand for? SCADA stands for Supervisory Control And Data Acquisition. It's a computer system for gathering, analyzing and processing data in real-time. Such systems were first used in the 1960s.


Related Articles

  1. What is SCADA?
  2. Where is it used? What industries?
  3. The value of SCADA.
  4. Capabilities of SCADA.
  5. How SCADA systems work.
  6. Example: simplest SCADA system.
  7. RTUs and PLCs to HMI
  8. Migrate to LAN from serial.
  9. Data presentation.
  10. How to Evaluate systems.
  11. RTU functions.
  12. SCADA Human Machine Interface (HMI) functions.
  13. Quality matters more than price.
  14. Surveying your remote sites.

The SCADA industry was born out of a need for a user-friendly front-end. The need was to control a system containing Programmable Logic Controllers (PLC SCADA). This supervisory system allows remote monitoring and control of an amazing variety of devices in industrial plants. This includes water and gas pumps, track switches, and traffic signals.

One of the key processes of SCADA is the ability to monitor an entire system in real time. This happens via data acquisition. These include meter reading and checking statuses of sensors. These data points are communicated at standard intervals depending on the system.

Besides the data being used by the RTU, it is also displayed to a human. The human is able to interface with the system to override settings or make changes when needed.

Modern SCADA systems have many data elements called points. Each point is a monitor or sensor and these points can be either hard or soft. A hard data point can be an actual monitor.

A soft point is an application or calculated value. Data elements from hard and soft points are usually always stored and logged to create a timestamp or history.

In essence, a SCADA application has two elements. They are:

  1. The process or system or machinery you want to monitor and control. This can take the form of a power plant, a water system, a network, or a system of traffic lights.
  2. A network of smart SCADA devices that interfaces with the first system through sensors and control outputs. This network is SCADA, meaning it gives you new abilities. You can measure and control specific elements of the first system.

Throughout this article, I'll also cover other concepts related to the application of this system.

What is SCADA?

There are three main elements to any system:

  • RTU's (Remote Telemetry Units).
  • Communications.
  • HMI SCADA (Human Machine Interface).

Each RTU collects real-time data at a site. Communications bring that information from the various plant (or regional RTU sites) to a central location. They can also return instructions to the RTU.

Communication within a plant is conducted by data cable, wire or fiber-optic. Regional systems most commonly utilize radio. The HMI is a PC system running powerful graphic and alarm software programs.

The HMI software displays this information in an easy to understand graphics form. It archives the data received. It transmits alarms. It also permits operator control as required.

How Does SCADA work?

Now, the initial question of "What is SCADA?" has been answered. The next step is to look at the way this system operates as a network.

A SCADA network consists of one or more Master Terminal Units (MTUs). These are utilized by staff to monitor and control a large number of Remote Terminal Units (RTUs). The MTU is often a computing platform, like a PC, which runs specialized software. The RTUs are most likely small devices that are hardened for outdoor use and industrial environments.


Want to Know More?


As we saw earlier, there are several parts of a working SCADA system. This system usually includes signal hardware (input and output), controllers, networks, user interface (HMI), communications gear and software. Altogether, the term SCADA refers to the entire central system. The central system usually monitors data from various sensors that are either in close proximity or off-site (sometimes miles away).

SCADA Components and Functions

A SCADA system performs four functions:
  1. Data acquisition.
  2. Networked data communication.
  3. Data presentation.
  4. Control.

These functions are performed by several kinds of SCADA components:

  • Sensors (either digital or analog) and control relays and timers. These directly interface with the managed system.
  • Remote telemetry units (RTUs). These are small units deployed in the field at single sites and locations. RTUs serve as local collection points for gathering reports from sensors and delivering commands to control relays to control equipment.
  • Master units. These are larger computer consoles that serve as the central processor for the SCADA system. Master units provide a human interface to the system. They automatically regulate the managed system in response to sensor inputs.
  • The communications network that connects the master unit to the RTUs in the field monitor at your remote sites.

How Can I Install a SCADA system?

There are five phases in creating a functional system:

  1. The DESIGN of the system architecture includes the communication system. Also involved in this initial phase will be any site instrumentation that isn't there yet. It will be required to monitor desired parameters.
  2. The SUPPLY of RTU, communication, and HMI gear. This consists of a PC system and the required powerful graphic and alarm software programs.
  3. The PROGRAMMING of the communication gear. and the powerful HMI graphic and alarm software programs.
  4. The INSTALLATION of the communication equipment and the PC system. The previous task is typically much more involved.
  5. The COMMISSIONING of the system, where communication and HMI programming problems are solved. The system is proven to the client. Operator training and operator manuals are also provided.

A complex SCADA system can be complex to configure. However, it is most likely much easier to operate.

Why Is SCADA So Popular?

SCADA systems are an extremely advantageous way to achieve industrial process monitoring and process control. They are great for small uses, such as climate control. They can also be effectively used in large applications. This could include monitoring and controlling a nuclear power plant, oil and gas plant, or transit system.

SCADA can come in open standard communications protocols. Smaller systems are very affordable. They can be purchased as a complete system. They can also be mixed and matched with specific components.

Large systems can also be created with off-the-shelf components. SCADA software can also be easily configured for almost any application, removing the need for custom software development.

How DPS Telecom Can Help You

As demonstrated in this knowledge base, building the right SCADA system for your business isn't simple. It's easy to spend more than you need. Still, there are ways to save money. You can improve efficiency in ways you don't want to miss.

It's hard to learn everything you need to know and still perform your daily job. We can help you plan your SCADA implementation, with expert consultation, training and information resources. DPS telemetry gear is built with the capabilities you need. We're committed to helping you get the best monitoring system for your specific needs.

We're here to help.

1-800-693-0351

Have a specific question? Ask our team of expert engineers and get a specific answer!

Ask an Expert DPS Telecom

Click here for more information.

Get the SCADA White Paper

Download our free SCADA tutorial.

An introduction to SCADA from your own perspective.

SCADA White Paper

Click here for more information.