Christos Dalamagkas Posted February 18, 2021 Report Share Posted February 18, 2021 I am using a Vision700 Unitronics PLC in order to access some measurements using Modbus TCP/IP. Hence, the PLC acts as Modbus slave. My issue is that I need multiple Modbus masters to connect simultaneously via Modbus TCP using the same TCP port of the PLC to access the measurements. However, my PLC actively rejects connection requests by responding with TCP RST, in case a TCP session has already been established with another Modbus master. Is it possible to permit multiple concurrent Modbus TCP sessions using the same TCP port? You may find attached the VisiLogic project of the PLC (version 9.8.31). High_Power_Generator_V4.vlp Quote Link to comment Share on other sites More sharing options...
AlexUT Posted February 18, 2021 Report Share Posted February 18, 2021 PLC is right. There is no support for concurrent connections to one TCP port. Define more ports as TCP Slave/Server for MODBUS TCP, and more connections will be accepted. *V700 support 8 sockets, so up to 8 external devices can connect to one V700./ 1 Quote Link to comment Share on other sites More sharing options...
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