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pCOWeb +030220966 – rel. 1.1 – 12.12.2017 37
7 BACNET
pCOWeb can recognise queries sent by a supervisor that uses the
BACnet protocol (Building Automation Control Networks), in the
following two versions:
BACnet/IP (Addendum A/Annex J)
BACnet Ethernet ISO8802-2 over 8802-3
The two standards use the same physical means for carrying the
data (Ethernet RJ-45 network) but differ as regards the different
ways the data packets are encoded. If BACnet is used, during
installation the proper version needs to be set to coincide with the
type used by the supervisor.
A complete description of the BACnet protocol is not within the
scope of this document. The system integrator, who is usually
responsible for setting the various parameters, checking network
communication and setting up the supervision system, should
know how BACnet works.
The basic BACnet parameter configuration page is shown in
Figure 7.a
.
IMPORTANT: all settings become active at next pCOWeb reboot.
For advanced configuration, go to
http://ksa.carel.com and
download the BACset software and the BACset user guide; the
main screen of this program is shown in
Figure 7.b
.
BACset can be used to set all the properties of the BACnet
objects supported by pCOWeb , save them on pCOWeb or on the
PC for later use when required.
The BACnet configuration is saved on
pCOWeb in a number of
files in the /usr/local/root/flash/etc/sysconfig directory in the same
way as the other configurations.
BACNET PICS
BACnet is a scalable protocol, that is, it features a vast array of
functions, some of which are obligatory, others whose
implementation is left to the discretion of the manufacturer. For a
product that uses BACnet, the document that analytically
describes the type of functions implemented is extremely
important.
This document is called PICS (Protocol Implementation
Conformance Statement) and for the
pCOWeb is available at
http://ksa.carel.com .
NOTE1: The clock on the
pCOWeb can be set using specific
commands in the BACnet protocol. When using this
method, it is recommended to disable time
synchronisation with
pCO controller or NTP (see
section 5 on page 29).
NOTE2: The number of mapped variables in
Figure 7.a
has to
be coherent with the number of variables sent in
supervision. Moreover when ModBus Extended
protocol is running is necessary that BACnet mapped
variables are less or equal to the number of variables
sent in supervision, see
Figure 9.l
and in every case
they could not be more than 2048 for each type (digital,
analog or integer)
Figure 7.a - BACnet: basic configuration
Figure 7.b - BACset software for the advanced
pCOWeb BACnet configuration