Triangle Tube’s ProtoNode Startup Guide
Page 15 of 40
ProtoCessor
1991 Tarob Court Milpitas, California 95035 USA
Web
RS-485 Bias Jumpers
Figure 9: Modbus RS-485 Biasing Jumpers on the ProtoNode N34 (left) and ProtoNode N35 (right)
•
An RS-485 network with more than one device needs to have biasing to ensure proper communication.
The biasing needs to be done on one device.
•
The ProtoNode has 530 Ohm resistors that can be used to set the biasing. The ProtoNode’s default
positions from the factory for the Biasing jumpers are OFF.
•
The OFF position is when the 2 RED biasing jumpers straddle the 4 pins closest to the outside of the
board of the ProtoNode. See
Figure 9
.
•
Only turn biasing ON:
o
IF the BMS cannot see more than one device connected to the ProtoNode
o
AND you have checked all the settings (Modbus COM settings, wiring, and DIP switches).
•
To turn biasing ON, move the 2 RED biasing jumpers to straddle the 4 pins closest to the inside of the
board of the ProtoNode.
3.2.1 Biasing the Modbus RS-485 Network