Airflow Duplexvent BV400 - 9.4 Modbus Connection

Fig. 2.1 RS485 Wiring Example
This document includes the protocol of Modbus communication that is used with ENECON
control boards.
Control board uses Modbus RTU protocol via RS485 connection. The unit works as Slave and
the information can be taken from an external Master module.
Connection information of the unit is listed as below:
Connection Type: Modbus RTU Slave
Standard Address: 1
Link speed: 9600
Party: None
Data Bits: 8
Stop Bit: 1
Communication network is showed below. Control board can be connected to RS485 on which is
connected more than one unit. Address conflicts on this line should be removed and necessary
software settings should be done for data communication.
If the line is too long or if any communication problem occurs, 120 Ohm resistance should be
added at the beginning and end of the line as shown on schema.
DI
D
D
DI DIDE DE
DE
DI
RO
RO RO
D
D
R
R
R R
A
B
120Ω 120Ω
B B
B
A
A A
DE
RO
RE
RE RE
RE
9.4 Modbus Connection
9.4.1 Introduction
9.4.2 Properties
9.4.3 Physical Connection
Page 15 of 32