Host Mode; Slave Mode; Device Parameters; Baud Rate Parameters - Ebyte E90-DTU User Manual

Chengdu Ebyte Electronic Technology Co., Ltd.

4.1.2 Host mode

M1 (bottom) and M0 (top) devices are in host mode. The radio configured in host mode can obtain and
configure the Modbus registers of the radio through the serial port. The parameters modified in host mode will take
effect immediately. In low power mode HMI, SCADA software and other Modbus registers The host device needs
to be connected to the host radio, and Modbus slaves such as PLC and remote IO need to be connected to the slave
radio.
In the host mode, the VOUT interface of the radio does not output power, and does not support automatic
serial port polling.

4.1.3 Slave mode

Both M1 and M0 dial up and the device is in slave mode. The radio configured as a slave cannot obtain and
configure the Modbus register from the serial port of the radio. It can only remotely configure parameters through
the connected host radio, and it needs to be restarted to take effect. Write 0001H to the device holding register
07EAH to restart the device.
In slave mode, the radio VOUT interface outputs power and supports serial port automatic polling function.

4.2 Device parameters

4.2.1 Baud rate parameters

check digit
The device only has one serial port that supports RS-485 and 3.3V-TTL serial port protocols, and does not
support simultaneous access to both interfaces.
If the RS-485 interface is used, it needs to be connected with the terminal equipment in the way of A to A, B to
B, and the GND between the devices can be connected at the same time;
If the 3.3V-TTL interface is used, the TXD needs to be connected to the terminal device RXD, and the RXD is
connected to the terminal device TXD, and the GND interface between the devices must be connected.

4.2.2 Local modbus address

The device supports configuration parameters through Modbus RTU protocol, so the device must have a
unique device address in the network (non-Modbus RTU protocol transmission can ignore the device address),
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Item
baud rate 1200、2400、4800、9600
data bits
NONE、ODD、EVEN
stop bit
Range
7、8
1、2
E90-DTU(400SL30L)_UserManual_EN
Defaults
9600
8
NONE
1
13