Multi-Host Mode; Storage Gateway - Ebyte E90-DTU-V8 User Manual

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Chengdu Ebyte Electronic Technology Co.,Ltd.

E90-DTU(433L30E)-V8 User Manual

5.8.3. Multi-host mode

There is only one Modbus master station for relatively simple protocol conversion, while the multi-master mode

can handle up to 4 Modbus TCP masters. One request is processed at a time, while the multi-host mode will be

sorted and processed according to the TCP request, and other links will wait), thereby solving the bus conflict

problem (currently only 4 host connections are supported), only supports working in TCP server mode, slave

machine Only in the serial port, otherwise it will not work properly.

With the increase of the number of hosts, the Modbus timeout time should be increased accordingly, and the

request interval should be increased. If multiple hosts are required to make continuous high-speed requests, it is

recommended to use a "storage gateway".

It is recommended to configure "Simple Protocol Conversion" when no multi-channel host is used.

Multi-host mode configuration (the picture on the left is the host computer, and the picture on the right is the

webpage):

The storage gateway not only arbitrates the bus data but also stores the repeated read commands. When different

hosts request the same data, the gateway does not need to query the register status of the RTU device multiple times,

but directly returns the data cached in the storage area. To a certain extent, the multi-host request processing

capability of the gateway is improved, and the time consumed by the entire request process is also shortened. Users

can customize the storage area command polling interval and command storage time according to their needs.

As the optimization of multi-host request performance, the storage gateway can only work in the TCP server mode,

which improves the response speed of the network side.

Features:

(1) The gateway has a 3K cache for storing instructions and returning results (reading 10 holding registers as an

example, about 100 instructions and returning results can be stored);

(2) The RTU response time-out automatically clears the cache to ensure the real-time and authenticity of the data;

(3) The polling interval can be customized, 0-65535ms (default: 500ms);

(4) The gateway will poll the RTU device according to the storage time of the instruction used for configuration. If

the MODBUS host does not query the instruction again during the storage time, the gateway will automatically

delete the storage instruction to release the cache;

(5) The first command and control command (05, 06, 0F, 10 function codes) will directly access the RTU device;

(6) Only 01, 02, 03, 04 Modbus function code query result storage is supported;

Storage gateway configuration (the picture on the left is the host computer, and the picture on the right is the

webpage):

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