December 2008

BTL Mark: Resolve interoperability issues & increase buyer confidence
BACnet Testing Laboratories

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The Front End
The chief reason for multiple systems under one Front End is to remove the perceived shackles of the control provider from the end user.

Darryl Trombley

Darryl Trombley
Building Automation Consultant
Metro Environmental, Inc.

Today’s climate of Open Systems, Competition and Integration has left many building owners and facility managers wondering what the heck they bought and has left them dealing with a Building Management System (BMS) that has created more frustration than help.

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The “Front End” is the term for the user interface for a BMS. Typically once a building, campus or business has a Front End in place, the push is for all controls that get installed thereafter be “open protocol”, which is typically BACnet or LON, to allow for competition for the building management system.

This is a flawed approach for several reasons. The BMS system has, in recent years, become a commodity item for a facility when in reality it is the furthest thing from a commodity item. This is the Interface between Man and Machine.

One for the price of two! (Merging two systems together)

When a differing controller is utilized under an established Front End, there are now typically two different programmers involved with the system. The Controller Programmer whose job is to make the equipment perform the tasks set forth by the engineer (Sequence of Operation) and the Front End Programmer who must adapt the controller to the user interface. Typically neither is familiar with the other system so both contractors have to be paid to create the interface.

Where are the energy saving features! (The disconnect between hardware and software)

A BMS control system consists of two basic pieces, Hardware and Software. The hardware turns things off and on (Fans & Pumps), opens and closes things (Dampers and Valves), and measures things (Temperature and Energy Usage). The software determines when the hardware changes what a piece of equipment is doing. It is the software that can determine that set points should be changed because the Electrical Demand is getting too high. It’s the software that starts a unit 15 minutes before the occupied time instead of 2 hours because the space temperature is only 2 degrees away from its set point. It is the interaction between the two pieces that the efficiencies come into play. When the controller is the same manufacturer as the Front End, these energy saving algorithms are easily accessed and adjusted because the programs running in the controller were developed by the Front End. Set points are easily accessed and adjusted. Trends, reports, schedules, alarms are all easily accessible by the end user via the Front End. It is this suite of software that makes a BMS an energy savings tool for the facility owner. When a differing manufacturer is used at the controller level, this interaction is severely limited. Any point that is viewed from the controller by the Front End must be programmed for the Front End to interact with it. Any set point that is adjustable from the Front End must be programmed for the Front End to interact with it. When this is the means of systems interacting, the inherent features of the software are lost because there are two different software packages handling every single user function.

Who you gonna call? (Difficult serviceability)

Typically when a problem arises, a facilities technician has to determine the cause. If a piece of equipment doesn’t respond to commands it can be difficult to determine where the breakdown in communications lies. It could be between the Thin Client (browser) and the Front End (server), the Front End and the controller network interface, or within the controller network itself. It becomes difficult for a facility technician or the maintenance personnel, whose expertise is usually more along the lines of mechanical systems, to know where to get help to solve the problem. If the wrong contractor is called first, then the business has to pay for their time as well as continuing to call and pay for other contractors until the problem is narrowed down and solved. This process takes time and money usually at the expense of comfort while it is being resolved.

But my other building looks different. (Inconsistency)

If a facilities manager is fortunate enough to have found a contractor that is comfortable adding differing controllers to the controller network and then adding these units into the User Interface, it is unlikely that the graphical interface will remain consistent from one portion of the system to the next. Programmers program to their level of comfort. The programmer who is an artist may take the time to add bells and whistles to a user interface that the owner may find useful. The owner may have points added or additional features added over time to make the User Interface more to his liking. If the control system is expanded by the low bidder who dabbles in Front End work, there is no time for the added systems to be groomed to match the existing graphics.

What is Integration? (Incorporation as equals into society or an organization of individuals of different groups) - Webster’s

The term integration is used very often in today’s discussions of BMS. Not unlike the definition from Webster’s Dictionary mentioned above, it is essentially incorporating two systems into one. There are many products in the BMS world that can share data. Data is easy, intelligence is another thing. Passing data can work very well from one controller product to another. However, again you are faced with two different programmers to put the two systems together in many cases. There are situations where Integration makes a lot of sense and then there are others that it makes no sense at all.

Examples of Good Integration:

Packaged Equipment – Chillers, RTUs, AHUs, Generators, etc… These types of machinery have sophisticated onboard control systems already in place and the level of interaction from a BMS is more monitoring points than running control sequences.
Existing Terminal Units – VAVs are the best example. There could easily be 50 VAVs per floor in a 5 story building. If there is an aging BMS in place and for the most part the VAVs are working OK, integration to the VAVs could work well to monitor the space temperatures and box flows. New controls could be installed to get better control of the Air Handlers, Boilers, Chillers etc… and increase efficiencies on the plant equipment. When the time is more appropriate for opening the ceiling, changing VAV controllers and installing new networks due to age of the VAVs or failures of old controllers, the savings from the earlier control retrofit assists in the higher cost of reworking the VAVs.

Examples of Bad Integration:

• New buildings with differing control systems – Many times in a campus environment there will be open bidding on the controls for a new building as if there was no Front End already in place, even when there is an established control system product in place. The idea is that if you buy control systems with Open Protocols such as BACnet and LON that anything will work together under one Front End. This is not unlike having several different email programs running within an office. Yes they can all send email but the capability of sharing calendars, contact lists, appointment requests would all go away. The use of a common Front End with differing control systems to save money on the install will more than be wasted in lost software capabilities and additional technical headaches.
• Multiple VAV box control manufacturers – The VAV box is viewed as an incidental control point. It appears there is not much happening that can impact the overall efficiency of the building so it doesn’t matter whose box controller goes in as long as the data feeds back to the Front End. This is incorrect. When installing new controls on a VAV system this becomes the tip of the spear for energy savings. This is where the interaction between the occupant and the HVAC system comes into play. When the VAVs match the Front End, the capabilities such as Manual Commands for Air Balance Contractors, Manual Override to make up for mechanical problems as well as in-depth trending for problem areas or tenants are exponential.

Reliable Controls I don’t want to be LOCKED into to a BMS Product. (Look for partners, not wardens)

To say you are locked into a control product means that you are held against your will. This is why the commodity approach to a BMS and the controllers beneath it is flawed. A BMS is perhaps the most crucial piece of the mechanical system. When a business’s computer system is implemented it is researched, selected, implemented and maintained. If a law firm uses Microsoft Windows they are not likely to allow one person to purchase a MAC because that is what he liked in college. This is a business and the team must use matching products to maintain the efficiency of the office. The BMS should be looked at the same way. Research the systems that are available and then select the one that best matches your needs.

The chief reason for multiple systems under one Front End is to remove the perceived shackles of the control provider from the end user. There was a time when the typical BMS was not very user friendly and the end user needed to either, place a service call to the BMS provider to make anything more than the simplest changes to their system, or become proficient enough with the software to learn to make the changes themselves. While some of these systems still exist, most systems today are very user friendly and can easily be managed by the average computer user. The days of a facilities technician and/or manager not being knowledgeable in use of a computer are gone. While there may be a few that “grew up” before the days of computers, most personnel that have risen to be responsible for building operations are well aware of how to use a computer, utilize the internet and to interact with the web browsers that have become the norm in today’s BMS world.

The control system provider of today should be looked at as a partner. These are the people who are keeping a finger on the pulse of energy conservation, sustainable buildings, and advancements in technology. These are not mechanics who hook up thermostats. The control system provider of today is a specialist who can help you maximize the return on your investment in a BMS. With the tools such as remote access, trending, reporting, and alarming coupled with a service contract that will keep the software current with the newest developments in energy saving algorithms and allow a skilled technician to be part of the facilities team, the owner will benefit from the BMS purchase.

About the Author

Darryl Trombley's background includes HVAC service tech, Chief Engineer (HVAC Maintenance), Control System Engineer, DDC Programmer, DDC System Trainer & Salesman. He currently works for Metro Environmental in the Detroit MI market.


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