The main focus of the Open Platform Communications (OPC) Foundation is to develop an open, flexible, plug-and-play standard that allows end users to enjoy an enormous choice of solutions, as well as greatly reducing development and maintenance costs for hardware and software vendors. In OPC, communication between data sources and applications takes place by employing a client-server software architecture which got rid of individual drivers used in pre-OPC period. The OPC classic has issues with security aspects and lacks several reliable characteristics like fault tolerance, redundancy, interoperability, and use of web-based technology. It provides interoperability among different fieldbuses, between controllers connected to Ethernet networks using different protocols like Ethernet/IP, PROFINet, etc. An OPC server can communicate with a data source provided the server is configured with the native protocol of the data source, irrespective of the data format. OPC communication module, sitting at the top of the three part server module, communicates with the OPC client.