SCADA is an acronym for Supervisory Control And Data Acquisition, which is a computer system for gathering and analyzing real-time data. Such systems were first used in the 1960s.
The SCADA industry was essentially born out of a need for a user-friendly front-end to a control system containing PLCs (programmable logic controllers). SCADA networks allow remote monitoring and control of an amazing variety of industrial devices, such as 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 is facilitated by data acquisitions. 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.
SCADA can also be seen as a system with 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 can be viewed upon as an application or software calculation. Data elements from hard and soft points are usually always stored and logged to create a time stamp or history.
In essence, a SCADA application has two elements. They are:
Throughout this article, we will not only be answering the question of "What Is SCADA?" but also discussing other concepts related to the application of this system.
SCADA can be used to manage many kinds of gear. Typically, SCADA systems are used to automate complex industrial processes where human control is impractical. Around the world, SCADA systems are used in many industries. These include:
Manufacturing:SCADA systems manage parts inventories for JIT manufacturing. They also regulate industrial automation and robots. To ensure good output, they monitor process and quality control.
Buildings, facilities and environments: Facility managers use SCADA to control devices. These include HVAC, refrigeration units, lighting and entry systems.
Electric power generation, transmission, and distribution: Electric utilities use SCADA systems to detect two key things. Those things are current flow and line voltage. They monitor the operation of circuit breakers. They also take sections of the power grid online or offline.
Water and sewage: State and municipal water utilities use SCADA to monitor and regulate water flow. They also track reservoir levels and pipe pressure.
Mass transit: Transit authorities use SCADA to regulate electricity to subways, trams and trolley buses. They also automate traffic signals for rail systems. They can track and locate trains and buses with SCADA. They can also control railroad-crossing gates.
Traffic signals: SCADA regulates traffic lights, controls traffic flow and detects out-of-order signals.
There are three main elements to a SCADA system:
Each RTU collects information at a site, while communications bring that information from the various plant or regional RTU sites to a central location. They also occasionally 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 fundamentally a PC system running powerful graphic and alarm software programs.
The HMI 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.
Now that 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 of 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 SCADA software. The RTUs are most likely small dedicated devices that are hardened for outdoor use and industrial environments.
As we saw earlier, there are several parts of a working SCADA system. A SCADA system usually includes signal hardware (input and output), controllers, networks, user interface (HMI), communications gear and software. All together, 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).
These functions are performed by several kinds of SCADA components:
Your SCADA master should display information in the most useful way. This allows your human staff to oversee operations. Your master should also intelligently regulate your managed systems.
Here's a checklist.
SCADA master essentials:
Flexible and programmable response to sensor inputs.
Look for a system that provides easy tools for programming soft alarms. (reports of complex events that track combinations of sensor inputs and date/time statements) and soft controls (programmed control responses to sensor inputs).
24/7, automatic pager and email notification.
Why pay personnel to watch a board 24 hours a day? If equipment needs human attention, the SCADA master can automatically page or email directly to repair technicians.
Detailed information display.
You want a system that displays reports in plain English. You need a complete description of what activity is happening and how you can manage it.
Nuisance alarm filtering.
Nuisance alarms desensitize your staff to alarm reports. Your people can start to believe that all alarms are nonessential alarms. Eventually they may stop responding even to critical alarms. Look for a SCADA master that includes tools to filter out nuisance alarms.
A SCADA system is a long-term investment that will last for as long as 10 to 15 years. So you need to make sure it will support your future growth for up to 15 years.
Redundant, geo-diverse backup.
The best SCADA systems support multiple backup masters in separate locations. If the primary SCADA master fails, a second master on the network automatically takes over. There is no interruption of monitoring and control functions.
Support for a lot of protocols and equipment types.
Early SCADA systems were built on closed, proprietary protocols. Single-vendor solutions aren't a great idea as vendors sometimes drop support for their products or even just go out of business. Support for a lot of open protocols safeguards your SCADA system against unplanned obsolescence.
Reliability and robustness.
These systems are used for mission critical industrial processes where reliability and performance are paramount. In addition, specific development is performed within a well-established framework that enhances reliability and robustness.
Maximizes productivity and ensures continuous production. SCADA's design is centered on multi-level redundancy to ensure constant communication and operation of your system.
Improve product quality.
Analyzes and controls the quality of manufactured products using standard SCADA functionality. This includes Statistical Process Control (SPC). Advanced statistical alarms allow your personnel to perform predictive calibration of process parameters. This prevents out-of-limit deviations before they occur.
Reduce your operating and maintenance costs.
Through the deployment of a centralized SCADA system you can significantly reduce operating and maintenance costs; fewer personnel are required to monitor field gear in remote locations. This results in increased operator effectiveness. Also, less maintenance trips are required. This results in decreased maintenance and training costs.
Integrate with your business systems.
A SCADA system can be easily integrated with your existing business systems, leading to increased production and profitability. In addition, this system implementation allows you to transform, analyze, and present real-time information. This info travels throughout the enterprise for prioritized decision-making.
Preserve your capital investment.
When you spend money to improve operations, you need to ensure prolonged use. SCADA's open system design protects against control system obsolescence. It can be easily scaled to meet growing demands on your operations.
There are five phases in creating a functional SCADA system:
A complex SCADA system can be complex to configure. However, it is most likely much easier to operate.
SCADA systems are an extremely advantageous way to run and monitor processes. They are great for small applications, such as climate control. They can also be effectively used in large applications such as monitoring and controlling a nuclear power plant or mass transit system.
SCADA can come in open and non-proprietary protocols. Smaller systems are very affordable and can either be purchased as a complete system or can be mixed and matched with specific components. Large systems can also be created with off-the-shelf components. SCADA system software can also be easily configured for almost any application, removing the need for custom software development.
As demonstrated in this "What is SCADA?" guide, building the right SCADA system for your business isn't simple. It's easy to spend more than you need, but there are also opportunities to save money and improve operational efficiency that you don't want to miss. It's hard to learn everything you need to know and still perform your daily job. DPS Telecom can help you plan your SCADA implementation, with expert consultation, training and information resources. DPS telemetry gear is built with the capabilities you need and we are committed to helping you get the best SCADA system for your specific needs.
There is no other network on the planet that is exactly like yours. For that reason, you need to build a monitoring system that's the right fit for you.
"Buying more than you need" and "buying less than you need" are real risks. You also have to think about training, tech support, and upgrade availability.
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