Video SCADA Tutorial: Sensors And Real-World Device Examples
In this video version of our popular SCADA Tutorial White Paper, you'll learn the basics of SCADA technology. Andrew discusses important checklists for evaluating SCADA remotes and SCADA masters. You'll also see real-world examples of popular sensors and...
SCADA Tutorial Video Review
Hi everyone. This is Andrew with DPS TV. Today I'm going to walk you through the basics of SCADA. In this video tutorial, I'll show you what SCADA can do for your network, how to save time and money with SCADA, and how to evaluate SCADA remotes and master stations.
Before we dive into all that, though. Remember that all the information I'm sharing with you today can be found in the SCADA tutorial white paper found online at www.dpstele.com/white-papers/
Ok, lets get started with some of the basics. SCADA stands for Supervisory Control And Data Acquisition. It's not a specific technology or protocol, but refers to any application where data is collected from a system in order to control that system.
I'll give you an example of the worlds simplest SCADA system. Imagine a fabrication machine in a factory that produces widgets. Every time the machine finishes a widget, it activates a switch that turns on a light. That light tells a human machine operator that a widget has been made.
Obviously a real SCADA system does a lot more than that but the idea here is the same. A full-scale SCADA system just monitors more stuff over much greater distances.
Now lets talk about the two elements involved in a SCADA system. All you need are the system or machine you want to monitor and control, and a data collection system made up of sensors and control outputs used to monitor and control the first system.
Now you know the basic concept of SCADA, lets look at the different industries that use it. Here are just a few examples.
Electric Utilities. Power plants use a SCADA system to detect current flow and line voltage, monitor circuit breakers, and even take sections of the power grid on and off line. Water utilities monitor and regulate water flow, reservoir levels, and pipe pressure. Building and facility managers use SCADA to control HVAC, refrigeration units, lighting, and building access systems. Mass transit authorities use SCADA to regulate electricity to subways, trains, and trolly buses. Rail systems even use it to automate traffic signals and control railroad crossing gates. This very short list is just the tip of the iceberg.
SCADA is used in nearly every industry and public infrastructure project because automation increases efficiency. And anything that increases efficiency is bound to help you reduce costs.
All right. Let's get down to business and see how a SCADA system works. Basically a SCADA system performs 4 functions: data acquisition, data communication, data presentation, and control.
So what kind of equipment do you need to accomplish this? SCADA equipment basically falls into one of four categories: sensors and controls that interface directly with the system you're managing, remote telemetry units (or RTUs) for data from the sensors and delivering commands to the relays, a SCADA master to service the central processor, and a communications network to connect your SCADA remotes to the master station.
Lets talk about sensors first because they're at the front line. They're going to play a huge role in your system. Sensors can either be discrete or analog. Discrete, also known as digital sensors, detect alarm conditions that can be reported as on or off. This could be like a motion sensor that was tripped. In our widget example, I can imagine that a laser trip sensor might be used to detect a widget having been produced and moving down a conveyer. Discretes can be accurately represented by a light turning on or off, just like in our widget example.
Analog sensors, on the other hand, answer the question how much. You'll use this sensor to monitor things where you need precise measurements, more than just a simple on or off - maybe for a good temperature reading or fuel level measurement.
You'll have to determine which sensors are best for your operations. But I can almost guarantee you that you'll have a mix of analog and discrete sensors.
I have some sensors here I'd like to show you. This is a two-in-one device that monitors both temperature and humidity in and around your equipment. This is for monitoring current. You simply run a wire through this hole and it will detect the magnetic field and determine the current flow going through. And it will output that information through these contacts to your RTU. This is a simple motion sensor. It's a lot like the one you may have in your home alarm system. You can focus it to a particular area to monitor something very specific.
This is an analog probe. You see it's very compact, mostly just a wire. This simple jack is just like a headphone, plugs right into your RTU. You've got about 7 feet of wire to work with. And you can attach the other end to sense the temperature of a specific piece of equipment. Finally I've got a water sensor. Obviously, water is a big enemy of computer systems. And this sensor, you can attach to the floor. And if a puddle ever formed and connects any of these contacts together, you get an alarm reported back up the wire into your RTU and to your master station, where you'll see it.
So these are just a few examples of things you might want to monitor in your SCADA system. For even more ideas, download the SCADA Sensor Whitepaper for a list of the top 10 sensor types.
Your sensors need a way to report their data, and that's where SCADA remotes come in. Remotes collect sensor data and equipment alarms and send them, generally across long distances, to your SCADA master station. I've got an example of an RTU here. This is the NetGuardian 216T. You see it's got a screen on the front, a nice sturdy metal box, and lots of inputs and outputs on the back for monitoring your system. Here's a helpful checklist to keep in mind when evaluating SCADA remotes. Sufficient capacity. Look for a remote that's got the capacity to handle everything you plan to monitor now, and leave room for expansion as your network grows. You shouldn't have to pay for extra capacity you're never going to use either.
Intelligent control. A remote with control relays and automation capabilities can save you an incredible amount of time by managing your SCADA system for you. You can program automatic responses for certain situations.
Rugged construction. You may have remote sites in areas with extreme highs or lows in temperature. A quality RTU should be tough enough to withstand the climate. Look for both a metal chassis and an industrial temperature rating.
Redundancy and power communications. You need your SCADA system up and running 24-7, right? Look for a SCADA remote that offers dual power inputs or battery backup. Just as important are redundant communication paths, so your sensor data can be reported even if your primary transport goes down.
Just like your sensors, your remotes need a place to report their data. That's the role of a SCADA master station. This is sometimes called an HMI, for human machine interface. Here's a list of the SCADA master must-haves.
The SCADA master you choose should display information in a useful clear way that gives you the information you need quickly.
Programmable controls. Look for a master that allows you to automate responses for sensory inputs or a common nation of sensory inputs and alarm events.
Multi-protocol and equipment support. A SCADA master is a long-term investment. So make sure it not only all the equipment you want to monitor now, but also the things you want to add later. You want a master that supports lots of equipment types and open protocols, so you can keep everything in one unified system. You're asking for trouble and extra costs when you start talking about multiple incompatible SCADA systems.
Nuisance Alarm Filtering. Over time, unnecessary alarms, also known as nuisance alarms, desensitize your staff from real network problems. This is a lot like spam in your email inbox. Yeah, it's annoying. But it also makes it harder to see important messages. Eventually a critical alarm is going to get missed and that could lead to costly damage.
24x7 email and pager notification. If an alarm really needs human attention, your master should alert you immediately with a page or email.
So what's the economic value of SCADA? Maybe you work in one of the industries that I mentioned and maybe you don't. But think about all the things that could go wrong in your operations and the impact it has on your output. If you're wondering exactly where a SCADA system could increase your efficiency, ask yourself these questions.
- Does the equipment in your network require uninterruptible power or total climate control?
- Do you need to know the real-time status of many different devices and components in a large, complex system?
- What equipment in your network do you need to operate from a distance?
- Do you need to measure how changing inputs affect the output of your operations?
- Where are you lacking accurate, real-time data for key processes that affect your operations?
If you're looking for help setting up or evaluating your SCADA system, call SCADA experts at DPS Telecom at 1-800-693-0351. For DPS TV, this is Andrew signing off.
Call 1-800-693-0351 to receive a:
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