Journal - BACnet Interest Group Europe eV

BACnet insight
The B-AWS has more stringent
requirements placed on it, including
a much larger set of objects
and properties which it must be
able to modify, and to configure
all standard alarm types intended
for operator notification.
Finally, the B-AWS is required to
support Event Log objects (objects
that record alarm histories)
in other device, including the
ability to display the objects’ recorded
alarm histories.
Scheduling
BACnet scheduling uses Calendar
and Schedule objects. A Calendar
object indicates whether today’s
date is in a list of dates within the
object; such as holidays for example.
A Schedule object contains a
standard weekly schedule, with
“exception schedules” to override
a day’s schedule completely or in
part or completely; for example,
scheduling a meeting for a conference
room.
The B-OWS is required to present
and modify the core properties of
Calendar and Schedule objects, in
particular lists of dates, weekly
and exception schedules. It is only
required to support three data
types including analog and multistate
values.
The B-AWS has additional re-
BACnet – bei guter Planung noch besser
Well-planned is even better – BACnet
Oliver Greune 1
Ein enttäuschter Endkunde, ein
frustrierter Systemintegrator gibt
es denn das mit BACnet? Leider
viel zu häufig; Warum ?
Die beste Basis,
dass es gut kommt
BACnet ist faktisch das beste
Kommunikationssystem der Gebäudeautomation.
BACnet ist
weder an einen Hersteller, noch
sonst an eine monopolistische
Technologie gebunden. BAC-
40
quirements – including the ability
to create and delete Calendar and
Schedule objects – and a much
larger set of properties which it is
required to be able to modify.
Trending
BACnet trending (or trend-logging)
is performed by two objects:
the Trend Log object and
the Trend Log Multiple object.
Both objects collect and record
time-stamp data, but the Trend
Log object collects data from one
property of one object in one device.
The Trend Log Multiple object
can trend multiple properties
of multiple objects in multiple devices
in the system.
The B-OWS is only required to
gather and present trend data
from Trend Log and Trend Log
Multiple objects 3 .
The B-AWS has a more comprehensive
set of requirements, including
the ability to create and
delete Trend Log, Trend Log
Multiple and Event Enrollment
objects, and to modify a number
of Trend Log and Trend Log
Multiple data collection parameters.
Device and Network
Management
BACnet defines the Device and
Network Management interoperability
area as “the exchange
net ist weltweit genormt, regionale
Dialekte gibt es fast nicht.
Geschützte Label dokumentieren
die Konformität eines Gerätes
gegenüber dem BACnet Standard,
geprüft durch unabhängige
Labore. Derzeit existieren zwei
Prüfstellen. Ein Labor in Indien,
welches überwiegend Geräte aus
Amerika prüft und zum Tragen
des BTL Logos berechtigt. In Europa
können BACnet Zertifikate
von WSPCert nach Bestehen der
BACnet Europe Journal 14 03/11
of data between BACnet devices
concerning the operation and
status of [the] devices.” This includes
a number of different types
of operations. Although there are
some common requirements for
both the B-OWS and B-AWS, the
B-AWS has additional requirements
on it, as follows:
The B-AWS is required to be able
to find and present a list of all
BACnet devices – at least those
that support BACnet’s device location
capability 4 – currently connected
to the BACnet system.
The B-AWS must be able to
present a list of all objects in a
particular device.
The B-AWS must be able to send
the “DeviceCommunicationControl”
command to another device
to order it to stop sending messages
for a specified time, or to restart
sending.
The B-AWS must be able to create
and delete objects in other devices.
The B-AWS must be able to order
other devices to restart using the
“ReinitializeDevice” command.
Finally, the B-AWS must be able
to backup and restore the configuration
of other devices using
BTL Tests, geprüft durch das akkreditierte
Labor WSPLab ausgegeben
werden. Der bestandene
Test erlaubt es Herstellern, die
Mitglied von BACnet International
sind, das Gerät in den USA
listen zu lassen und das BTL zu
tragen.
Der BACnet Standard ist jedoch
nicht starr, er wird seit ca. 20
Jahren kontinuierlich von den
Mitgliedern der BACnet Inte-
BACnet’s “Backup and Restore”
capability.
Summary
Superficially, B-OWS and B-AWS
workstations offer relatively similar
features, and many B-OWS
will incorporate some of the additional
capabilities of the B-AWS.
But as described here there is actually
a broad range between the
two profiles, which should be
considered when comparing and
specifying B-AWS and B-OWS
workstations.
2 Herunterzuladen unter http://www.
ashrae.org/technology/page/20.
Downloadable from http://www.
ashrae.org / technology / page / 20.
3 Trend Log ist nur erforderlich, wenn
die B-OWS als ein Gerät mit bezeichnet
wird.
Trend Log Multiple required only if
the B-OWS is designated as a device
with “Protocol_Revision ≥ 7.”
4 Bekannt als DM-DD-B, oder Who-
Is/I-am messaging, das von praktisch
allen BACnet Geräten unterstützt
wird. Derzeit sind nur MS / TP
slave Geräte davon ausgenommen.
Known as DM-DD-B, or Who-
Is / I-am messaging., which nearly
all BACnet devices support. Currently
only MS / TP slave devices are
exempt.
rest Groups weiter entwickelt.
Dazu gehören Institutionen wie
z. B. Universitäten, bedeutende
Endkunden oder Systemintegratoren
und natürlich Gerätehersteller.
Letztere nehmen den
grössten Einfluss. Fortlaufend
werden Innovationen und Anforderungen
in sogenannten Addenda
dem BACnet Standard hinzugefügt.
Regelmässig, ca. alle 4
Jahre, werden diese Addenda in
den BACnet Standard integriert