Multi-Host Mode - Ebyte NB1A1 User Manual

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5.4.3 Multi-Host Mode

Relatively simple protocol conversion can only have one Modbus master station, while
multi-host mode can access multiple Modbus TCP hosts at the same time. When multiple Modbus
hosts access at the same time, the Modbus gateway will perform bus occupation scheduling (RS-485
bus can only process one request at a time, and the Modbus can only handle one request at a time).
The multi-host mode will sort and process according to the TCP request successively, and the other
links will wait), so as to solve the bus conflict problem (currently, in the server mode, a maximum of
16 Modbus TCP host connections are supported, and the simultaneous access of multiple hosts
should pay attention to the matching of request interval and timeout time. Otherwise, the serial port
transmission rate is much lower than the Ethernet transmission rate, resulting in packet loss. If you
need a fast response, you are advised to use the storage gateway.) The server can work only in TCP
server mode, and the slave can work only over a serial port.
As the number of hosts increases, the Modbus timeout period should be increased accordingly. If
multiple hosts need to make continuous high-speed requests, it is recommended to use "storage
gateway", and it is recommended to configure "Simple protocol conversion" when no multiple hosts
are used.
For software configuration and register configuration, refer to "Simple Protocol Conversion" and
enable multiple Modbus Poll software at the same time (3 channels are used as an example, a
maximum of 8 channels can be supported in the server model).。
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