The aims of the OPC Classic standard are as follows:
- To structure the data on the server side in order to simplify the data gathering on the client side
- To define the communication services and the standard mechanisms to exchange data
Basically, the OPC Classic standard works as follows:
- The server manages all available data.
- The server sends queries for the data coming from the devices on demand and updates an internal cache on a regular basis. The server initializes and manages a cache for each group of variables requested by an OPC client. The scan rate related to an OPC client group cannot be less than the scan rate used by the OPC server to gather the data from its devices to update ...
