AutomatedBuildings.com Article - Using SCADA Systems in an HVAC Environment

There is a misconception in the commercial controls and HVAC industry today that SCADA (Supervisory Control and Data Acquisition) systems are not applicable, nor are they cost effective in this marketplace. Typically, these systems come with a high price tag and feature rich technology which, for many of the smaller HVAC market applications, is truly not cost effective. But in the larger markets, such as high-rise office buildings and multiple building systems (including schools, colleges, data centers, and government facilities) they actually make more sense.

One of the most attractive financial features of these products is that they are supported by organizations that are truly “Systems Integrators.” This is defined as an organization whose sole purpose is their procurement and pursuit of new business and service work; whose success does not rely on a single vendor’s product. Instead, it is dependent on their employee talent pool and their technical ability to provide value-added features and application services to help their customers to be more productive.

How is this different than the typical HVAC system with DDC Controls? Unlike the traditional DDC system from any of the manufacturers, the SCADA systems truly empower the end users (owners). They have a choice on who performs services on those systems, based on quality and price, rather than being held captive to the proprietary systems of the past, where the tools and application databases were held by the manufacturer’s branch office or single authorized representative.

The technology exists today to allow owners to have a truly open system in the same manner as the PC industry today allows us to purchase a PC from one vendor, an Ethernet card from a second, and printers and peripheral devices from others, and have them seamlessly interoperate using a common platform. SCADA systems provide a better environment to accomplish this than any of the HVAC manufacturers can, using their “Front End” software.

Here is an example of an actual customer who has taken the time and effort to realize this opportunity….

The New York City School District has approximately 1200 schools throughout ten regions, which include all of the five boroughs of the New York City area. They are Manhattan, Brooklyn, Queens, Staten Island and the Bronx. They are also building 75 new schools as part of their “Children First” program to provide an optimal environment for the city students to better learn and develop their educational skills in the K-12 market.

Historically, the district had constructed 70 new schools back in the early to mid 1990’s time period, and used the traditional methods of construction where there was a general contractor, mechanical, electrical, and plumbing sub-contractors, and many different third tier sub-contractors. One of these was the temperature controls contractor, who was under the mechanical contractors’ scope of work. The district ended up with many different manufacturers’ systems, as well as many different system architectures, components, software, and even PC hardware in each of these buildings.

This was impossible for the city to maintain or service. They could not get qualified competitive bidding for service, and it was also impossible for the city to train their staff on all of the different types of systems in those buildings. There was no consistency from one school to the next when it came to the control systems, the controllers, and even the color graphic screens, even though the buildings were very similar in design.

The end result, in the late 1990’s, was that the district decided to go back to using pneumatic controls for all of their construction work, which in itself is a standard (20 psi). The district never gave up hope that there would ultimately be a better solution to what they felt was a common problem. They strove to somehow provide a cost effective system that could be installed and maintained by multiple companies, thus creating a “Durable Competitive Environment” for the district.

Soon thereafter, they made a decision to use the LonTalk Protocol (referred to as “Lon”) as developed by Echelon www.echelon.com in 1988, which has since become an ANSI standard as an Open Protocol ANSI709.1. They were very impressed with several features of the protocol, one of which was that there was a common software tool that allowed them to handle all of their network management and the sharing of data between controllers throughout the network. This process is known as “binding”. This tool has the ability to be licensed to the school district, and reside on a server as part of their shared network. They were also impressed that many of the major manufacturers were producing controllers using this technology, as well as many other specialty companies for items such as metering and lighting. Equipment manufacturers were also getting on board by offering Lon control options pre-packaged with their equipment direct from the factory.

These were all features that the district had been searching for, but there was one piece of the puzzle that was missing. How do they take all of these controllers and provide a common HMI (Human Machine Interface) that will accomplish the same goal?

Their search ended up with an RFP for SCADA systems software solutions from companies such as Wonderware, Intellution, and Allen Bradley, all of which have the ability to utilize the driver available from Echelon that allowed systems of these types to seamlessly monitor and control these networks. Our proposal included the use of the Wonderware solution www.wonderware.com, and Control Technologies was selected as their “Master Integrator” (see this press release for more information http://www.echelon.com/company/press/2005/nyc_school.htm).

If you take the time to analyze the features and power of these SCADA systems, you will realize that these systems are actually a perfect fit for these types of applications in the HVAC environment. These were never considered in the past since all DDC systems for the HVAC industry were strictly proprietary with custom code and protocols developed by the manufacturers from the controller level to the enterprise level as one system. There weren’t any opportunities for owners, nor integrators for that matter, to even consider looking into any type of driver development since there would certainly be nothing but resistance from the manufacturers, and perhaps ensuing legal action.

The industrial market has had open systems for over 20 years and all of the manufacturers develop products and services to compliment these systems. In many cases, it’s a specialty item that is developed using standard protocols so that customers will welcome the opportunity to add this to their network. It was common practice for integration companies to bid on projects for services against each other for the same customer over and over again, unlike the commercial controls industry where the contractor who won the first phase of a project typically “locked in” the customer for a 10-15 year period.

This practice goes against our core values of what we believe in as individuals, owners of businesses, and Americans. Our nation is one that awards us choices in everything we do, so it is a natural progression to provide for this in our Facility Management Systems. Today, contrary to what some companies would like you to believe, that means open systems utilizing protocols such as BACnet, LonTalk, and Modbus on the device level, with SCADA Enterprise level systems at the top of the network architecture.

These systems are made to handle a wide array of real-time data throughput while, at the same time, offering common database structures for alarming and historical data archiving. Because of this, it’s a natural progression to have an owner integrate accounting systems, automate work orders, order entry, security, and even point of sale systems into this architecture through the use of open database structures, which are already built-in.

The NYC School District has taken advantage of this and so have many others throughout the country. In doing so, owners must be careful that the software utilized for the application programs on the device level gets licensed and turned over to them prior to project completion. This is where the partnership with the Master Integrator becomes well worth the investment. We make sure that the bid documents are “fool proof” so that the contracting industry cannot take advantage of the ambiguities in any portion of the specifications or drawings that will affect the integrity of the project for the owner. It is not sufficient just to state that systems shall use these open protocols.

In summary, owners of larger facilities as well as multiple building owners will surely benefit from the SCADA Systems once thought of as only for industrial process control. These systems have the speed and horsepower to accommodate all types of applications. It also allows the owner to take advantage of building an architecture that is “truly open” and will provide the protocols, software, and hardware tools to offer choices on vendors, contractors, and service organizations. This must start at the design level. To guarantee that you will get what you paid for, partner with a Master Integrator before the project begins.

Ron has been in the controls and building automation business since 1981 where he started in sales in the New York Metro area. Ron was the National Manager of Distribution for Invensys Building Systems (now TAC), before joining Control Technologies in April of 2002 where he started and developed the NY metropolitan office for CTI.

Ron has been involved with large System Planning & development with companies such as Exxon Mobil, Duke University Medical Center, Yale University, Fletcher Allen Health Care, Bank of America, Verizon Wireless, NYC Schools, and more.

Ron is a LonMark Certified Professional and now heads up the Integration Services Group on a corporate level for CTI, who has offices in New York, Massachusetts, Vermont, New Hampshire and California.

Copy write - Ron Padilla, Control Technologies, inc. 2008, used with permission.

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