If you are interested in deploying a new SCADA system into your network, it's important to fully understand SCADA applications. After all, the bottom-line value of your SCADA system depends on the proper application of your solution.
At DPS, we've been designing and manufacturing custom remote monitoring applications for decades. Since we're experts in remote monitoring and control, we've seen all kinds of scenarios in terms of different usage for SCADA systems. We know how important it is that you know how to apply the monitoring and control capabilities to your specific network, this way you can make the most out of your investment.
So, let's explore some facts about SCADA, where you can deploy SCADA systems and some applications for these systems.
Supervisory Control and Data Acquisition (SCADA) is not a specific technology, but it's a type of function. This means that any device that gets data about a system in order to control that system is a SCADA application.
SCADA applications have two elements:
The process/system/machine you wish to monitor. This can be a power plant, a water system, a network, a system of traffic lights, or anything else.
A network of intelligent devices that interfaces with the first system through sensors and control outputs. This network, which is the SCADA system, gives you the ability to measure and control specific elements of the first system.
The components of a SCADA system are:
Sensors - either digital or analog - and control relays that directly interface with the managed system.
Most of the site control performed by a SCADA system is actually done automatically by two types of devices, either RTUs or PLCs.
Data such as equipment status and meter readings are collected at the RTU or PLC level. If a system is designed to support alarm collection, that will also be done at this level.
The SCADA HMI serves as the master station that communicates the processed status and alarm information collected along the SCADA system to the human operator.
The HMI combines these pieces of data from the system into one place, saving operators from manually combining polled data from individual points.
Operators can view the system alarms and information through the HMI, and they can make educated decisions based on these readings. If a system is equipped with control functions, signals can be sent back to the RTUs to execute certain functions.
The communications within these SCADA systems were initially designed to take place over radio, or direct modem, or serial connections. Nowadays, is more usual to have Ethernet or IP over SONET for SCADA system communications.
For security reasons, SCADA information should be kept on closed LAN or WAN networks that prevent sensitive data from being exposed to outsiders over the Internet.
SCADA systems provide companies monitoring and control applications by collecting and analyzing real-time data. Though not all SCADA systems are equipped for controlling functions, they are still referred to as SCADA systems.
You can use a SCADA system to perform four functions:
SCADA systems usually need to monitor hundreds or even thousands of sensors. Some sensors measure inputs into the system (for example, water flowing into a reservoir), and some sensors measure outputs (like valve pressure as water is released from the reservoir).
Some of those sensors measure simple events that can be detected by a straightforward on/off switch, called a discrete input or digital input. You can use these sensors to measure simple states, such as whether the equipment is on or off.
Some sensors measure more complex situations where exact measurement is important. These are analog sensors, which can detect continuous changes in a voltage or current input. You can use analog sensors to track fluid levels in tanks, voltage levels in batteries, temperature, and other factors that can be measured in a continuous range of input.
For you to be able to monitor multiple systems from a central location, you need a communications network to transport all the data collected from your sensors.
Sensors and control relays are very simple electric devices that can't generate or interpret protocol communications on their own. Therefore, an RTU is needed to provide an interface between the sensors and the SCADA network.
You can use the RTU to encode sensor inputs into protocol format and forward them to the SCADA master. In turn, the RTU can also be used to receive commands in protocol format from the master and transmit electrical signals to the appropriate control relays.
You can use a SCADA master station to perform several different functions and data presentation is one of their main ones.
The master continuously monitors all sensors and alerts the operator when there is an alarm. An alarm here means when a control factor is operating outside what is defined as its normal operation. The master presents a comprehensive view of the entire managed system and presents more detail in response to user requests.
The master also performs data processing on information gathered from sensors. It maintains report logs and summarizes historical trends.
SCADA systems can be used to automatically regulate all kinds of industrial processes. For instance, if too much pressure is building up in your gas pipeline, you can set your SCADA system to automatically open a release valve. Another example is electricity production that can be adjusted to meet demands on the power grid.
So, a full-scale SCADA system can be set to adjust the managed system in response to multiple inputs.
You can use SCADA to administer any kind of gear. Usually, SCADA systems are used to automate complex industrial processes where human control is unworkable, such as systems where there are more fast-moving control factors than humans beings can comfortably manage.
SCADA systems can be used in:
Electric power generation, transmission, and distribution
Electric utilities use SCADA systems to detect current flow and line voltage, to monitor the operation of circuit breakers, and to take sections of the power grid online or offline.
Water and sewage
Water utilities use SCADA to monitor and regulate water flow, reservoir levels, pipe pressure, and other factors.
Buildings, facilities, and environments
Facility managers use SCADA to control HVAC, refrigeration units, lighting and entry systems.
SCADA systems manage parts inventories for timely manufacturing, regulate industrial automation and robots, and monitor process and quality control.
Transit authorities use SCADA to regulate electricity to subways, trams, and trolley buses, to automate traffic signals for rail systems, to track and locate trains and buses, and to control railroad crossing gates.
SCADA regulates traffic lights, controls traffic flow, and detects out-of-order signals.
This short list of examples don't list all the possible applications for SCADA systems. SCADA is used in probably every industry and public infrastructure project - anywhere where companies and agencies need automation to increase efficiency.
Therefore, the way you'd use a SCADA system would depend directly on the kind of industry you're in.
You probably already know where you could apply a SCADA system in your operations. But, what kind of real-world results can you expect from using SCADA?
The following points are just a few things you can with the information and control capabilities you get from a SCADA system:
Access quantitative measurements of important processes, both immediately and over time.
Detect and correct problems as soon as they begin.
Measure trends over time.
Discover and eliminate hindrances and inefficiencies.
Control larger and more complex processes with a smaller, less specialized staff.
Ultimately, a SCADA system gives you the ability to improve your knowledge of your networks. You can place sensors and controls at every critical point in your managed process, and as your network grows you can put sensors in more and more places. As you monitor more things, you have a more detailed view of your operations - and most important, it's all in real time.
So, even if you have very complex manufacturing processes, large electrical plants, etc., you can have a better view of every event as it's happening. This means that you have a knowledge base from which to correct errors and improve efficiency. With SCADA, you can do more, at less cost, providing a direct increase in profitability.
The simplest possible SCADA system example would be a single circuit that notifies you of one event.
Imagine a fabrication machine that produces widgets. Every time the machine finishes a widget, it activates a switch. The switch turns on a light on a panel, which tells a human operator that a widget has been completed.
A real SCADA system does more than this simple example. But, the principle is the same. A full-scale SCADA system just monitors more things over greater distances.
Now that we took at a very simple example of the usage of a SCADA system, let's dive into a more realistic scenario.
Imagine that your SCADA system monitors around a thousand of single sensors in your network. If two sensors sent major alarms through the monitoring system, your SCADA master would be alerted. If one of these alarms shows an outage at your site, and another shows a battery failure at the same site, the RTU would get these inputs, translate them, and send them to the master.
The system master would then react to this alarm combo. It uses a user set control relay, such as turning on the back-up generator at the site, stopping a network failure. Your monitoring system saves costs on repairs and lost revenue due to network downtime.
Building the right SCADA system involves important decisions. 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.
Sometimes it's hard to learn everything you need to know while still performing your daily job. So, to help your SCADA implementation, our monitoring experts have put together the SCADA Tutorial White Paper.
This white paper will explain the essentials of SCADA technology, give you guidelines for evaluating SCADA technology, and help you decide what kind of SCADA system is best for your needs.
If you want more information about SCADA applications, simply download your free copy of the SCADA Tutorial White Paper.