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Frequently Asked Questions
Demand-control ventilation (DCV) provides two benefits: energy conservation and indoor air quality maintenance. Indoor carbon-dioxide concentration is a function of human population density. It varies linearly with changes in the number of people occupying the space. On one hand, eliminating ventilation altogether to conserve energy places people at health risk. On the other, pre-set, fixed outdoor air intake leads to excess heating and cooling when building population is low. Automatic adjustment of ventilation assures indoor air quality (IAQ) at the lowest possible cost.
I have an old energy management system. Do I have to replace it to upgrade with LonMark-compliant controls?
No. It is usually possible to preserve capital investments in older systems while expanding or updating your facility with LonMark-compliant controls. The secret is to deploy internet technologies with a common database. HTML graphical user interface (GUI) and platform-independent database means you have a standard human-machine interface for the old and the new.
Most often economical operation and a comfortable indoor climate are quite compatible. Over the years I have discovered that uncomfortable buildings are usually inefficient buildings. Understanding and regulating enthalpy are helpful toward efficient operation. In owner-occupied facilities, energy may only represent 6% of total costs whereas salaries and benefits may represent over 60% of total costs to the owner. Excellent indoor climate (comfort and quality) significantly impact morale, attendance and productivity.
A historical perspective helps understand Lon control systems. In the early days of pneumatics, a sensor from one manufacturer would not work with another's controller and that controller would not be compatible with a pneumatic actuator from a third manufacturer. Over time, a 12-pound standard (3-15 psi) came to govern all manufacture of pneumatic controls. Now, pneumatic components are interoperable with one another. Echelon Corporation developed a standard for interoperability, LonMark-compliance, that has been adopted by almost every control systems manufacuter. Even peripheral manufacturers, like Belimo, offer components equipped with Lon communications. The LonMark standard is to DDC systems what the 12-pound span was to pneumatics: true interoperability.
Why do some manufacturers promote BACnet and others promote LonMark? Which protocol best serves the customer?
Some manufacturers prefer BACnet because it is royalty-free;other manufacturers deploy LonMark-compliant products because they can be readily integrated with other manufactuers' LonMark-compliant controllers. Echelon Corporation, creator of the LonMark standard, earns credits (royalties) for every LonMark-compliant controller shipped and installed. Niether protocol limits our capacity to integrate one protocol with another. We believe LonMark systems offer superior performance. And, the Lon standard offers the best hope for preserving capital investments in control systems from generation to generation. It can be said the LonMark standard is proprietary, and that is true. But, I do not see that as a negative. On the contrary I see that as a plus for the sake of uniformity and backward compatibility. For these reasons, and others, we believe LonMark-compliant systems are a better choice for the customer.
There is a trade magazine devoted to "Machine-to-machine", or M2M, systems. Is this important to building control systems?
M2M refers to a consolidation of data from disparate computer-based systems into a common database and uniform person-machine interface. For example, a building input power meter communicating via Modbus RTU practically communicates with HVAC DDC controls "speaking" LON while the chiller features a BACnet interface. Meanwhile the operator interface GUI publishes this data through HTML web-based pages. We have deployed systems with uniform GUI screens that display concurrent data from two dissimilar automation systems. To the customer, M2M means there is no penalty for migrating from one proprietary automation system, say a Johnson Contorls Metasys, to a Honeywell XL5000 or a Landis & Gyr system. Ultimately, a true M2M system actively shares data between systems seamlessly and in a timely way.
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