NAPOPC DA Server is an out-of-process OPC (OLE for Process Control) server which uses an Explorer-style user interface to display a hierarchical tree of devices and groups with their associated tags. A group can be defined as a subdirectory containing one or more tags. A device may have many subgroups of tags. All tags belong to their device when they are scanned to perform I/O
OPC is a series of standards specifications. The first standard (originally called simply the OPC Specification and now called the Data Access Specification) resulted from the collaboration of a number of leading worldwide automation suppliers working in cooperation with Microsoft