I need to read the values from an OPC server which is reading data from a Siemmens PLC installed on a machine. then set an interval of time to archive this information to a sql server database.

all i know about this topic is:

1.I can access the data at the OPC server using DDE though excel or calc of OOo.
2.Using spreadsheets for colecting the data is not rwally an option.
3.Visual Foxpro has some DDE functions but i honestly don't understand them very well, mostly because they are conecting to an excell spreadsheet and not to the OPC server directly.
4.there are several OPC clients to achive this, but they are quite expensive ($3,000.00) so I am looking for an inexpensive way to do it with VFP9


do you guys know a way to do so using DDE from withing VFP, or maybe an API call?