ProtoNode FPC-N34 & FPC-N35 User Manual
CHAPTER 3
– Interfacing ProtoNode to Devices
OMM-0150_B
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3.3 BACnet MS/TP, Modbus RTU or Metasys N2 (FPC-N34): Wiring
Field Port to RS-485 BAS Network
•
Connect the BACnet MS/TP or Metasys N2 RS-485 network wires to the 3-pin RS-485
connector on ProtoNode FPC-N34 as shown below in Figure 3-5.
o
The RS-485 GND (Pin 3) is not typically connected.
•
See Chapter 5 for information on connecting to BACnet/IP network.
•
If the ProtoNode is the last device on the on the trunk, then the end of line (EOL)
termination switch may need to be enabled. See Figure 3-6 for the orientation of
switch positions referenced below.
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).
Figure 3-5: Connection from ProtoNode to RS-485 Field Network
Figure 3-6: RS-485 BMS Network EOL Switch
•
If more than one RS-485 device is connected to the network, then the field bias
resistor switch may need to be enabled to ensure proper communication. see the
Figure above for the orientation of switch positions referenced below.
o
The default setting from the factory is OFF (switch position = right side).
o
To enable biasing, turn the bias switch ON (switch position = left side).
BMS RS-485
Wiring
ProtoNode
Pin #
Pin
Assignment
RS-485 +
Pin 1
RS-485 +
RS-485 -
Pin 2
RS-485 -
-
Pin 3
RS-485 GND
Bias Resistor Switch
G
-
+
End of Line Switch
