lp-548 Rev. 000 Rel. 004 Date 1.11.19
3
CAUTION
Use the mounting template and screws provided with the adapter. Damage to the MODBUS/BACnet adapter or appliance due to installation
with other mounting screws IS NOT covered by warranty.
When mounting the unit, keep in mind that the top cover must be removed to connect the RS-485 communication cable, and that the
appliance communication wire must reach the control inside the appliance.
The MODBUS/BACnet adapter can be mounted on the side of the appliance OR the wall next to the appliance, as long as care is taken to avoid
components behind the mounting surface. The mounting location must be within 3 feet of the appliance controller in order to be plugged
into the controller input port.
In BIC-926 based appliances, the four pin connector from the adapter must be plugged into the white connector labeled X3 on the
control.
In BIC-928 based appliances, the four pin connector from the adapter must be plugged into the black connector labeled X4 on the
control.
In both cases the adapter end of the four pin cable MUST be plugged into the BLACK connector labeled BIC X3 of the adapter circuit
board!
NOTE:
It is not recommended to install the MODBUS/BACnet adapter inside the appliance housing. Doing so may affect appliance operation
or damage the MODBUS/BACnet adapter.
A. BMS Wiring Requirements
RS-485 Communication Bus
•
Maximum length: 4000
feet
•
Cable specification: 24
AWG / A,B (twisted pair)
and GND shielded, with
characteristic impedance:
120 ohm
•
Maximum load: 32 units
(32 nodes)
Wires will be passed through the
PG connector on the side of the
adapter, then connected to the
three position connector marked
“X5” on the circuit board inside the
adapter. A label is provided inside
the adapter to ensure proper
connections of A, B, and GND. Two
wires (MB IN and MB OUT) may be
attached to each X5 screw.
See Figure 3 for an example wiring
diagram.
Figure 3 - Jumper Configurations in a MODBUS / BACnet Network
CAUTION
Damage to MODBUS/BACnet adapter or appliance due to improper installation IS NOT covered by warranty.
B. Jumper Setting
The appliance display handles
most of the MODBUS/BACnet
adapter configuration. There is
one jumper on the MODBUS/
BACnet adapter. When this jumper
is in place (factory default) it
connects a termination resistor
across the data lines of the RS-485
connection. Leave the jumper in if
the MODBUS/BACnet adapter is at
the end of the RS-485 bus. Remove
the jumper if the MODBUS/
BACnet adapter is one of many
connections and not at the end of
the bus. See Figures 3 and 4.
Figure 4 - MODBUS Termination Jumper Location (Highlighted in Grey)
