MULTI-VARIABLE MONITOR - MANUAL
21 | MVM – Manual | AntecControls.com
BACnet MS/TP
TYPICAL BACNET WIRING
NOTE:
Installer must use a 120-ohm resistor at the BACnet MS/TP end of line termination on the MVM.
What is BACnet?
BACnet is a communication protocol for communication
between the MVM and the devices with which it is
communicating. BACnet communication allows the MVM to
communicate with other BACnet MS/TP or BACnet IP devices
to display environmental and status values from those devices.
Network Addressing
When configuring the MVM, 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
Physical Connection
BACnet MS/TP consists of a 3-wire network architecture.
Daisy chain the +, -, and COM connections of all devices on
the network segment as shown in the figure below.
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 – network terminals. Remove the termination
resistor or disable any network terminations on all devices
when adding devices to an existing network segment.
BACnet IP can also be used to connect the MVM to an
existing IP network. It can then communicate with other
BACnet IP devices. If using this method, ensure the MVM’s
DHCP setting is enabled or that a static IP has been assigned
to the MVM.
Wiring Requirements
•
Twisted pair
•
Shielded (either foil or braided shields)
•
Characteristic impedance: 100 – 130 ohms
•
Capacitance between conductors: Less than 30pF per
foot (100pF per meter)
•
Maximum length of MS/TP Segment: 1050 feet (320
meters)
•
Maximum number of devices on MS/TP Segment: 32
