Procure BACnet System
BACnet was designed to allow communication of building
automation and controlsystems for applications such as heating, ventilating, and
air-conditioning control (HVAC), lighting control, access control, and fire
detection systems and their associated equipment.
The UDP port number 47808 (in hexadecimal, X'BAC0') identifies
BACnet messages and is the UDP port used by PAD devices. BACnet/IP devices use this
UDP port by
default but may be configured to use a different number if necessary. An
open protocol should be powerful and robust, capable of meeting all future
communication needs, as well as the present needs throughout all system levels.
Any communication protocol which doesn't meet these criteria should be
eliminated from further consideration.
BACnet's open structure and object-oriented commands
enables developers to provide enhancements or features, while still maintaining
full interoperability for all core operations. If use of a new control feature
becomes widespread and there is a need for it to be standardized among vendors.
ASHRAE provides a procedure for it to be adopted as a standard BACnet object or
service.
BACnet is a widely accepted, non-proprietary open
protocol standard. Companies began announcing their support for BACnet even
before the final draft of the standard was released. The fact that ASHRAE
developed BACnet plays a significant role in this acceptance. ANSI perceived
BACnet to be a significant development and adopted it as a protocol standard
within months of acceptance by ASHRAE.
Components vs Systems
For many years the BACnet
community has worked hard to ensure that BACnet is a global standard and that
it’s implemented consistently across multiple supplier product lines.
BACnet International devotes substantial resources to the BACnet Testing Lab
(BTL) and to annual device “plugfests” to support that objective. We
regularly point out that BACnet is a global consensus standard and we trumpet
the value of standards. We talk about component interoperability and in
some cases even interchangeability. All of this is good. Users need
to understand the power of standards and how specifying systems that
incorporate BACnet can add value to their building automation investments.
However, by promoting BACnet as standard and then using the shortcut term
“BACnet System” we invite the unschooled to mistakenly extend the concept of
“standard” from the communications protocol to the system. That seems to
lead some of them to the conclusion that all “BACnet Systems” are essentially
equivalent and can be procured like commodity products … even to the point of
the “reverse auction” procurement process for an energy management system I
recently encountered.
Reverse Auction Procurement
Reverse auctions have been
around for more than a decade. They evolved as a “simple” way for buyers
to drive down the cost of components. The essence of reverse auctions is
that suppliers bid back and forth for a well-defined piece of business on the
basis of price. Full-featured web platforms have evolved to support this
purchasing model but, even so, it has its limitations. One of the biggest
limitations is that for it to be effective, the product and its associated
transaction attributes (e.g. lead time, delivery date, etc.) need to be
unambiguously defined in terms that can be readily measured. And therein
is the rub. Energy management and building automation systems are complex
so fully defining all of the important attributes is a huge challenge.
Leaving any important attribute undefined results in suppliers compromising on
those unspecified attributes to achieve the lowest cost and win the
business. On the surface the result might look like a good deal for the
buyer. But those compromises might well come back to haunt the buyer in
the long run.
Lessons Learned
It was an attempt to give people new to the
BACnet community some insights based on the experience of people who have
already designed and operated systems built around BACnet. One of those
“lessons learned” was that a “BACnet System” is still a system. The BACnet
standard can make system integration faster, simpler and more effective but it
is not a substitute for system expertise, creativity or design rigor. Nor
does BACnet provide any assurance of product quality or system
effectiveness. These come only through knowledge and experience.
So, I encouraged owner/operators to develop a partnership approach to working
with suppliers who have that knowledge and experience. I saw first-hand what
happens when complex systems procurement is driven from a “first cost”
perspective without sufficient focus on supplier partnerships.
Benefits of BACnet Protocol
Benefits of BACnet Protocol
- Single operator workstation for
all systems
- competitive system expansion.
- Eliminates fear of being an
owner to be locked in with a single vendor.
- Possibility of integrating all
BAC Functions.
- Interoperability
·
Data sharing
·
Alarm and event management
·
Trending
·
Scheduling
·
Remote device and network management
Summary
BACnet is a standard. All
the necessary elements are in place: strong customer demand, a robust open
standard and manufacturer's support of the standard. BACnet seems to provide a
complete solution to interoperability issues for building procurement team. Understanding the
difference is important in establishing a procurement process that builds
positive supplier relationships and generates maximum value in acquiring an
energy management or building automation system. SSA Integrate can guide how to utilize this.
