CAVA - MANUAL
BACnet MS/TP Network
NOTE:
BACnet is only used on Cava™ when it does not
have a RIN connection to a Pace™ controller in the room.
What is BACnet?
BACnet MS/TP is a communication protocol for
communication between Cava™ and the building
automation network. BACnet communication allows the
end user to verify rooms and fume hoods are operating as
expected and allows them to set up trends to monitor
safety, and any alarms that occur.
If no Pace™ controllers are present in the space, a single
Cava™ in the room can act as the access point to BACnet.
All of the fume hood’s information transmits through this
one Cava™ to the network.
Network Addressing
When configuring Cava™, the user needs to assign the
unique identifying address for the room.
On any BACnet MS/TP network:
•
MAC Address can be between 0 and 127 and must be
unique to the MS/TP segment.
•
Device Instance can be between 0 and 4,194,303 and
must be unique to the facility.
•
Baud Rate can be 9,600, 19,200, 38,400, or 76,800
and must match that of the Router/System Controller
for the MS/TP segment.
BACnet Points
See Cava™ Product Submittal at
BACnet Points List.
Physical Connection
BACnet consists of a 3-wire network architecture. Daisy
chain the +, -, and COM connections of all devices on the
network segment. A BACnet MS/TP segment has a limit
of:
•
Maximum of 32 devices
•
Maximum length of 1050 feet (320 meters) for the
whole segment
When using shielded cable, ground the shield at one end of
the network segment only. Connect the shield of the cable
entering a device to that of the cable exiting the device.
Terminate the MS/TP network segment at each end of the
network segment by connecting a 120-ohm resistor
between the + and – terminals. Remove the termination
resistor or disable any network terminations on all devices
when adding devices to an existing network segment.
Wiring Requirements
Refer to your Antec Controls Wiring Diagram Package for
typical wiring requirements and recommendations.
Typical BACnet Wiring
NOTE:
Installer must use a 120 ohm resistor at the BACnet end of line termination.
When using non-isolated power supplies (i.e. Transformer
secondary common connected to ground), do not reverse 24VAC
polarity on any device, as it is critical to the network health.
CAUTION
