Civil Engineering Reference
In-Depth Information
BACnet/IP is better equipped to handle BACnet broadcasts over IP than
PAD devices.
It allows devices to enter the system from anywhere in the IP inter-
network.
It supports 'native IP' BACnet devices such as unitary controllers which
send and receive BACnet messages within IP frames, effectively using IP
inter-networks as BACnet LANs.
Basically, BACnet/IP devices communicate using IP messages in lieu of
BACnet messages, allowing the devices to be easily added to any IP inter-
network. Broadcasting messages continued to be a problem and have been
solved using one of the two methods outlined in Annex J called 'Multicasting'
and 'BACnet/IP Broadcast Management Device' or BBMD.
In Figure 6.9, every BACnet device is an IP device, so they can be connected
directly on intranet or Internet. Every BACnet subnet is an IP subnet.
6.6 Use of Internet technologies at management level
Currently, it is a trend in the BAS and IB industry to use Internet technologies
at management level to develop BAS and IB systems, particularly manage-
ment software and integration of BAS via the Internet. Many efficient and
convenient tools, methods and packages for applications on inter-networks
are available. Market pressure has seen a very quick process of selection,
and the survivors are used and accepted by many (if not most) users. For
instance, many BAS/IB management software packages have now been
developed using HTTP and Internet browsers. This means the management
functions of many other devices can be added easily into the management
software packages, such as digital CCTV monitoring and control. The use
of Internet technologies for developing BAS/IB management software has the
following advantages:
It allows the management software to be developed much more quickly at
a low cost, as many standard functions and tools can be used and adopted
directly.
It means that management software packages developed are more open
in terms of protocol and technologies. Thus it is easier for ordinary users
to use them as they are similar to other software packages used in daily
work or life. That is appealing to users.
It means software packages can easily adopt the management functions of
new 'third-party' devices and systems, as many of the current hardware
devices are developed to be Internet compatible.
When integration of BAS with the Internet at management level is considered,
current applications can be illustrated by two typical categories of integra-
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