我理解的不管您使用USB-MPI还是RS232-MPI,只要能连接上PLC就可以使用OPC Server的,那个USB连上后在你电脑上是一个com口把。您参考下下面链接http://forums.ni.com/t5/NI-LabVIEW-CVI-%E6%95%B0%E6%8D%AE%E9%87%87%E9%9B%86%E7%AD%89%E4%BA%A7%E5%93%...
还有个是教你如何使用OPC server与PLC通信的http://www.ni.com/white-paper/7450/zhs/
我刚查到一些资料,貌似opc server确实不支持usb-mpi,您可以咨询下西门子公司那边有没有什么解决方案。
下面是我找到的一些讨论:
“I called the other asking if I can make a try on S7-MPI with Siemens PC MPI-
USB adaptor. The OPC only accept com1, com2, etc but not be able to deal
with USB serial. We are going to buy one adaptor as your help suggested. ”
“I just ordered a Siemens S7 MPI PC adaptor (6ES79720CA230XA0) as suggested
in your OPC help manual, I hope I can connect to NI OPC Siemens S7 MPI.”
最后给出的那个适配器是232-MPI的。。。。