Controller Area Network (Canbus) - Price Antec controls CAVA Manual

Controller Area Network (CANbus)

What is the Controller Area Network?
The Controller Area Network (CANbus) is a communication
protocol that allows the Fume Hood Valve Module (FVM)
and the Sidewall Velocity Sensor (SVS) to communicate
with Cava™. By transmitting data from the SVS to Cava™
at high speeds and relaying changes to the FVM, Cava™
can ensure that the fume hood is always in safe operating
conditions.
Network Addressing
CANbus devices will come from the factory with
predefined MAC addresses. No addressing on-site is
required.
Typical CAN Wiring
CAUTION
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.
NOTE: Installer must use a 120 ohm resistor at the CANbus end of line termination.
6 | CAVA – Manual | AntecControls.com
Physical Connection
CANbus consists of a 3-wire network architecture. Daisy
chain the CANH, CANL, and COM connections of all
devices on the network as shown below. A CANbus
segment has a limit of:
•
3 Sidewall Velocity Sensors (SVS)
•
1 Fume Hood Valve Module (FVM)
•
A maximum length of 650 feet (200 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 network at the end of line CANbus device by
connecting a 120 ohm resistor between the CANH and
CANL network terminals. The network may fail to function
without the 120 ohm resistors in place. Remove the
termination resistor when adding devices to an existing
network and re-install it on the new end of line device.
NOTE: Cava™ has a built-in end of line resistor for CANbus
and must be an end of line device.
Wiring Requirements
Refer to your Antec Controls Wiring Diagram Package for
typical wiring requirements and recommendations.
CAVA - MANUAL