Data Modeling – The Future of SCADA?

SCADA systems have undergone numerous evolutions since their inception many decades ago. Innovations in technology and control systems have led software developers to develop new SCADA software to keep up with the changing industrial workplace. Data Modeling is one of the many new features some of the pioneering SCADA developers are introducing. The idea is that the complexity of large systems with numerous assets can be reduced, making the entire systems more understandable and manageable using a data model.

Anyone involved in process automation has had the misfortune of trying to make sense out of many different types of data from many different sources. When HMI screens are bound directly to data coming from PLCs, there are several problems that can emerge:

  • First of all, creating the screens and data bindings requires an intimate knowledge of the many memory addresses in each logic controller – this means there is usually only one individual or a small group capable of creating or modifying the screens.
  • This also means that the PLCs have to be running and returning live data while the HMI screens are being set up – this can lead to unnecessary downtime and more complicated deployments.
  • Any change in the process or processes requires a time significant investment in modifying the HMI displays to coordinate with the new data.

With a little imagination, I’m sure most people can think of several other drawbacks to binding HMI graphics directly to PLC memory addresses.

How Does Data Modeling Help?

In the world of SCADA, a data model is a logical representation of a real world system. A data model contains instances of all assets that are to be measured, along with properties of those assets (i.e. temperature, velocity, volume, etc.). When using a data model, HMI graphics are bound to properties of these assets rather than the actual data. The actual data is read to the model and the HMI updates accordingly.

Data modeling provides a number of advantages:

  • Creating HMI screens and data bindings does not require knowledge of the specific memory addresses since the graphics are bound to the model – screens can be created quickly and easily
  • HMI screens can be created independently of the PLCs – this means the entire SCADA system can be set up without having to take the process down.
  • If assets are lost or changed – or new ones are added – simply update the data model and every instance of the asset can be modified simultaneously – this means HMI screens can be reused instead of recreated, saving countless hours of development and training time.
  • A well-designed data model can give a unique overall perspective on a process that makes it easier to make plans and decisions about how the data can be used to make improvements.

Data modeling also allows new types of data to be monitored and controlled. Your data model can include work orders, purchase requests, human resources, supply chain data – in short your entire enterprise can now fall under the watchful eye of your SCADA system. This creates whole new possibilities for management and strategic planning.

Case in Point

Consider a recently developed SCADA application from B-Scada: Status Enterprise Edition. Status Enterprise allows users to create a logical model of their enterprise, including everything from equipment to users. Each type of equipment can be created with all associated properties, alarms and historical records. If there are 1000 instances of a particular asset, just create the type once and automatically generate 1000 instances of it. Assets can be grouped into collections, or one asset can be subordinated as a component of another (i.e a motor that has a cooling fan as a component). Work orders, maintenance records and troubleshooting guides can be created and associated with particular assets.

Aside from making data more manageable, modeling can also make creating HMI screens much easier. Imagine you have 1000 motors that each have a unique temperature value, a unique RPM value, a unique asset tag, etc. Since each of these motors is an instance of the same type, one screen template can be created for that type. That template can then be used to create 1000 unique screens for each instance of that type. This can save a tremendous amount of time (and money) in developing or updating a SCADA system.

Data modeling is not a new idea, but it is fairly new to the world of SCADA software, and it seems a safe bet to assume that it is not going anywhere. In fact, it’s likely that it will eventually be the way that all SCADA software operates. 

What’s Wrong with My Antique HMI? It’s a Classic!

You would think that if you plan to pay someone to sit in front of a screen (or a bunch of screens) all day every day, you would want those screens to be as effective and performance-oriented as possible. You would think that every possible effort would be employed to ensure that this employee was given all of tools available to assist him/her in performing his/her assigned duties. That’s what you would think.

Unfortunately, for many process control operators and technicians, this is not the case at all. They are relegated to using screens designed 20 years ago or more, using outdated graphics and without any concept of the HMI design best practices that have been developed over the last couple of decades.

You would think that the research on industrial accidents that has pointed unequivocally to poor HMI screen design as a primary contributing factor in process failures that have cost millions of dollars – even killed several people – would lead our captains of industry to recognize the hidden cost in employing outdated screens. You would think all kinds of things that are apparently not true if thinking is something that you’re into.

So, why is nobody upgrading their HMI displays? Money. The cost is too much when people are of the belief that what they have works just fine. The problem is that it is not easy to quantify the cost of what could be, and so people are left with just the cost of what is. And, frankly, what is isn’t good enough.

What makes a good HMI screen? There are different schools of thought on that, but there are some factors that most agree are necessary in a high performance display:

  • Clarity – Graphics are easy to read and clearly show the process state and conditions. Graphics will display relevant information and not just data. Alarms and indicators of abnormal conditions are clear and prominent.
  • Consistency – Graphics are standardized and consistently formatted. Interaction requires a minimum of keystrokes or pointer manipulations. Navigation is arranged in a logical, heirarchical manner.
  • Feedback – Controls will function consistently in all situations. Important actions have confirmation mechanisms to prevent inadvertent activation. Design principles are employed to reduce user fatigue.

Of course, much more can be said on the subject, and much more has been written. There are numerous best practices and techniques that can be used to ensure your HMI screens are efficient and performance-oriented. Too few of them are.

It is a researched and verified fact that an improved HMI means fewer accidents, less downtime, less human error, greater efficiency, and greater anticipation and control of abnormal conditions.

The next time you consider how much it would cost to upgrade your HMI displays, do yourself a favor and consider how much not doing it is already costing you.

How SCADA Shapes the World (Part 1 – Water)

There was a time when hearing someone use terms like scum, sludge, or grit chamber would have made me think I was listening in on the creation of a new comic series or primetime TV drama. Now, when I hear these terms (which, incidentally, is not often) I know that I am actually listening in on a discussion about something much more significant. These are terms used in the waste water treatment industry. I know “waste water” is not really a hot buzzword with the kids today, but it is very important aspect of today’s efforts to conserve and sustain our precious resources. And does a resource get any more precious than water? I think not.

So, what does this blogger think he’s up to writing about waste water treatment on a blog that has been clearly dedicated to SCADA? Well, that’s about as good of a transition as I can muster.

The waste water treatment industry has become one of the largest consumers of SCADA software. It just so happens that the treatment process is one that lends itself quite nicely to the features of a SCADA deployment, and the success of such deployments has only accelerated the trend.

A powerful SCADA system has optimal tools for enhancing operational efficiency, from detecting leaks to controlling distribution. One immediate benefit facilities receive after implementing a visualization solution is that small leaks can be detected before they become larger and a major (more expensive) problem. By carefully monitoring the conditions through each stage of the treatment process, the slightest abnormality becomes immediately noticeable. Detecting small problems before they become larger can save facility operators and maintenance technicians a tremendous amount of time – and the facility itself will save money.

Before SCADA, technicians would have to go out in the field to manually inspect gauges on each individual tank. Pump stations would be visited daily. Now, all of these conditions can be monitored remotely, allowing technicians to focus on improving plant operations and increasing efficiency. All of this has led to an increase in the output of accountable water.

So, SCADA is helping water treatment facilities save time, money, hardware and – most importantly – water. No wonder more and more facilities are implementing SCADA systems. Water treatment is just another one of the many ways that SCADA is helping shape the world in which we live.

(For more information on SCADA in water treatment, or to view a case study, visit our website.)