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4 Modbus TCP to SST Automation-defined
Protocol
4.1 Description
GS11-MT acts as a Modbus TCP server at the Ethernet side, and the serial protocol is SST
Automation-defined protocol. Modbus TCP communication and serial communication of GS11-MT are
independent, and exchange data between through the input and output data buffer inside GS11-MT. User board
can exchange data with EMT331 according to the SST Automation –defined protocol of GS11-MT.
The procedure of message transmission is as follows:
GS11-MT
SST-defined protocol
Modbus TCP
Request1
Request2
Request
…
Request a
Request b
Request
…
Response1
Response2
Response
…
Response a
Response b
Response
…
In this mode, Modbus TCP only supports 03H
、
04H
、
06H
、
10H function codes.
Note: In this mode, each Modbus TCP client just transmits one request message, and do not transmits another
request message until the Modbus TCP client receives the response or the response timeout.
The corresponding relationship of data buffer and function codes is as follows:
