ABB CBXi Series User Manual

CBXi IP Controller | Installation
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Subject to change without notice
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41
MAN0141 rev 2
3
CONNECT THE CBXI TO BACNET MS/TP
If the CBXi unit will be used with a BACnet MS/TP fieldbus, connect it as described in the following section.
MS/TP Cabling Requirements
Note: Use Copper or Copper Clad Aluminum 70 °C conductors only.
Terminals
PCB mounted plug terminal
connections
Conductor Area
Max: AWG 12 (3.31 mm2)
Min: AWG 22 (0.355 mm2)
Max cable length
1.2 km @ 38K4 baud
TERMINATE THE MS/TP NETWORK
If the CBXi-8R8(-H) is the first or last device on
the RS-485 network, then its MS/TP subnet
terminator switch must be set to “in”
ATTACH RS-485 COMMUNICATION WIRES TO THE MS/TP SUBNET PORT
Wiring the RS-485 network involves connecting the A+ (95) and B- (96) terminals in a daisy-chained
configuration. One end of the network will be connected to the Fieldbus of the CBXi. At the other end of
the network, the last device must be “terminated” by either installing a 100 Ω … 120 Ω resistor or, if the
last device is a CBX, users can switch the MS/TP Subnet terminator switch (located beside the MS/TP
port) towards the icon. This will effectively terminate the network.
The shield (screen) must be carried through the entire network, and must be grounded at one point on
the network as shown below:
CBXi-8R8(-H)
Network Segment
end
- - - - - -
CBX/CBV/CBT
Network end
Shield connected at end
of network only
Network
Termination
switch set to
ON
Shield continuous
throughout the
network
Network cable
segment daisy-chained
to next device
Network
Termination switch
set to ON at end of
network
Shield connected to
earth at one end of
network only

ABB CBXi Series Specifications

General

Brand	ABB
Model	CBXi Series
Category	Controller
Language	English