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29
Modbus RTU is the main station.
5
Use
TCP
Client
Realcom Protocol
When using a multi-port server as a
TCP client and the virtual serial port is
used, it is best to use the Realcom
protocol.
6
No Use
TCP
Client
None
Suitable for a large number of devices,
connected to a cloud way. And under
normal circumstances the cloud is a
server of public network IP on the
Internet.
7
No Use
TCP
Server
None
Suitable for devices and computers in
the same local network, do local
monitoring, no need to communicate
across the Internet.
5.1 Virtual Serial Mode
If the user software is using COM port for communication, it must use virtual serial
port mode. Including some PLC software, configuration software, instrument
software, etc.
Then check whether the monitoring computer and equipment are in the local
network:
1) If the computer is a public network IP server rented over the Internet, then the
device must use TCP client mode to connect the device to the server. At this
point, you can select the (2) and (5) in Table 6, and must select (5) if it is a
multi-port server.
2) All in the local network (can ping each other), then see is the upper computer
active query or device active send data. If the device is sent initiatively it must
use the device to be TCP client as (2) in Table 5, or you can choose the (1)
way.
5.2 Direct TCP/IP Communication Mode
If Modbus TCP conversion is not required and virtual serial port is not required, the
user software may directly communicate with the network port of the serial port