8
Modbus slave signals can be directly connected with the building automation system for parameter design and
data acquisition purposes. UNOnext acts as a Modbus slave device through pin 8 (RS485 B) and pin 9 (RS485 A) of the
UNOnext terminal block. The RS485 Baud rate is 9600bps, the parity is 'none', and the default slave address is 0xD0. For
detailed settings and data capture fields, see the UNOnext Modbus file
The figure above illustrates the traditional Modbus network architecture. The central control unit can be connected to
multiple devices in a linear topology. Cables must be terminated at both ends. Each device has a built
-
in 120
Ω
terminal
resistor. You can use the first pin of the DIP switch to turn the terminal resistor on or off. Except for the terminal device, which
must be set to on, every other slave device must be set to off. The default Modbus slave position of each device is 0xD0, and
the slave position of each device must not be repeated. In order for the central control unit to receive the correct data, the
second to fourth pins of the DIP switch must be used to set the device slave position.
IX. Wiring diagram –
Connecting to ventilation equipment (smart sensor control mode)
Mode 1, Ventilation equipment is controlled through RS485. The wiring diagram is as shown in the figure below. In addition,
the 8th pin of the DIP switch must be turned off. The settings are as follows
DIP Switches
8
On
Off
I. This controller controls ventilation equipment through RS485. If you do not know whether or not the equipment brand
and model is supported, please contact the dealer for technical support before purchase.
II. If, after evaluating the site
’
s environment, ventilation equipment cannot operate at full speed due to certain reasons
(excessive noise or vibration, etc.), the maximum wind speed can be set by adjusting the DIP switch. There are three stages
that can be set through the 6th and 7th pins of the DIP switch.
Controller
