Bacnet Ms/Tp Field Devices: Wiring Field Port To Rs-485 Network; Figure 5: Connection From Gw-Bac1 To Rs-485 Field Network; Figure 6: Rs-485 Eol Switch - Unitronics GW-BAC1 User Manual

Unitronics's BACnet Gateway User Guide
2.3

BACnet MS/TP Field Devices: Wiring Field Port to RS-485 Network


Connect the BACnet MS/TP RS-485 network wires to the 3-pin RS-485 connector on GW-BAC1 as shown
below in Error! Reference source not found..
o
The RS-485 GND (Pin 3) is not typically connected.

See Section 3 for information on connecting to BACnet/IP network.

If the GW-BAC1 is the last device on the BACnet MS/TP trunk, then the End-Of-Line Termination
Switch needs to be enabled (Error! Reference source not found.).
o
The default setting from the factory is OFF (switch position = right side).
o
To enable the EOL Termination, turn the EOL switch ON (switch position = left side).
BMS RS-485
Wiring
RS-485 +
RS-485 -
-
Unitronics
GW-BAC1 Pin
Pin # Assignment
Pin 1 RS-485 +
Pin 2 RS-485 -
Pin 3 RS-485 GND

Figure 5: Connection from GW-BAC1 to RS-485 Field Network

Figure 6: RS-485 EOL Switch

-
G
End-of-Line Switch
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