RS485 TO ETH ( B)
Figure 33 Monitor sending and receiving data
7 .
MODBUS ADVANCED FUNCTIONS
The serial port server with Modbus gateway function does not have station address and
registers. It is a communication bridge. It will generate Modbus according to the Salve ID,
function code, register number and number of registers in the Modbus TCP command sent by
the user software to the Modbus gateway. RTU designates and outputs from the serial port.
Think of it as a protocol "translator".
7 . 1 . ENABLE MODBUS GATEWAY
First of all, the serial port server should support Modbus gateway, that is, the "Modbus TCP
to RTU" function in Table 5 Device Supported Functions in the Device Settings dialog box should
be ticked.
By default, the serial server is in normal transparent transmission mode. If you need to
switch to Modbus gateway mode, please select the option "Modbus TCP Protocol" in
"Conversion Protocol". After that, the device automatically changes the "port" parameter to 502
(the port of the Modbus server). Then the Modbus gateway is enabled.
If the serial port RTU device is used as a slave station, the host computer Modbus TCP
software connects to port 502 of the Modbus gateway. At this time, the Modbus gateway needs
to work in TCP server mode; if the serial port RTU is used as the master station, the Modbus
gateway works as a TCP client and the destination IP Fill in the IP of the computer where the
Modbus TCP software is located, and the destination port is generally 502.
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