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CONNECTING BACNET
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CONNECTING BACNET
As of June 2009 BACnet connectivity is in final development. The instructions that follow
may change. Contact the iCOMM™ administrator at 888 928-3702 to ensure you have the
latest BACnet installation and connection instructions before proceeding.
BACnet is a standardized building automation network communications protocol. The
BACnet protocol allows appliance manufacturers to supply equipment that can
communicate with BACnet compliant supervisory controls and building management
systems. The iCOMM™system’s CM (communication module - page 6) supports only MS/
TP communications.
This section provides instructions for connecting the CM to a customer’s BACnet compliant
supervisory control or building management system. BACnet connections to the CM and
appliance configuration on the customers building management system software should
only be performed by the customer’s BACnet administrator.
iCOMM™ may be setup to use BACnet apart from the web interface. This is shown on the
main display as “BMS mode only.”
SUPPORTED WATER HEATING APPLIANCES
All iCOMM™compatible water heating appliances will be able to communicate with BACnet
compliant supervisory controls through the iCOMM™ system’s CM (communication module)
- see Table 2 on page 11.
Limitations
The goal is to communicate all the process values available at an iCOMM™ compatible
water heating appliance’s display to a BACnet supervisory control.
The iCOMM compliant water heating appliances themselves may contain more information
than can be supported by BACnet as there is a limit of 75 process values (BACnet objects)
per device/appliance. A process value might be a simple on/off switch or as complicated
multi-state value such as control state, but each counts as one of the 75 object per device
limit. Every effort has been made to provide the most information possible.
This interface is not electrically isolated from earth ground but is loosely referenced to earth
ground by the heating appliances. The heating appliances are connected to earth ground
and therefore earth ground is connected to the iCOMM through the network cable with a
minimum of 100 ohms resistance. The BACnet Data+ and Data- signal should not be at a
potential greater than 10V from earth ground to prevent communication problems or
damage.