BMS RS-485 Wiring
Flow Computer COM Card
Pin #
Pin
Assignment
RS-485 +
Pin 4
RS-485 +
RS-485 –
Pin 3
RS-485 –
End Of Line Termination
Pin 2
Terminating Resistor
-
Pin 1
RS-485 GND
KEP Multi-Protocol Communication Card Option Start-up Guide
Page 11
4.2 BACnet MS/TP or Metasys N2 (Option 3): Wiring Field Port to RS-485 Network
Figure 6: Connection from COM CARD to RS-485 Field Network
•
Connect the BACnet MS/TP or Metasys N2 RS-485 network wires to the 4-pin RS-485 connector on
COM CARD Terminal Block as shown below in
Figure 6
.
o
The RS-485 GND (Pin 1) is not typically connected
•
See
Section
5.4
for information on connecting to BACnet/IP network.
•
If the COM CARD is the last device on the BACnet MS/TP or Metasys N2 trunk, then the End-
Of-Line Terminating resistor (180 Ω) needs to be activated by placing a jumper from terminal pin
2 to terminal pin 3 on the multidrop cable end station.
