网络传输控制信号，网络芯片是W5100,传输信号可为控制信号与开关信号，modbus通信协议。-PLC TO W5100,the led and i/o can traver bay w5100,use msp430f5438 as cpu,modbus an 485 to the sevlers,pc use to controle.

vb调用winsocket控件，通过modbus TCP 协议与IO设备控制。-A VB program for communicating with I/O equipment by modbus Tcp protocol. in which winsocket activeX is loaded.

OPC转换为MODBUS O PC转换为MODBUS-OPC to MODBUS OPC to MODBUS OPC to MODBUS