基于西门子s7-200PLC控制器。SJ-VI型教具PLC源程序，程序是用梯形图编写。-Based Siemens s7-200PLC controller. SJ-VI aids PLC source program is written with a ladder.

vb2007 与 PLC通讯的测试编程,采用vb语法结合梯形图编程的结构编写的，希望能给大家有少少帮助。-vb2007 test communication with the PLC programming, the vb syntax combined with the structure of the ladder programming prepared, I hope we can have some help.