ClimateWorx ProtoNode Start-up Guide
Page 15 of 46
4.2.1 Biasing the Modbus RS-485 Device Network
An RS-485 network with more than one device needs to have biasing to ensure proper
communication. The biasing only needs to be done on one device.
The ProtoNode has 510 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. (
Only turn biasing ON:
o
IF the BMS cannot see more than one device connected to the ProtoNode
o
AND all the settings (Modbus COM settings, wiring, and DIP switches) have been
checked
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.
RS-485 Bias
Switch
(off)
Figure 11: Modbus RS-485 Biasing Switch on the ProtoNode N34 (left) and ProtoNode N35 (right)
