TILI Automation

 This article is about Open Platform Communication (OPC) which is one type of communication protocol used in industrial automation. As we know that Data is transferred from field to controller by using some sort of communication method. OPC Classic is one type of method used to transfer data from field device to controller and from controller to HMI. You receive every kind of signal from value to error to alarm generation in real-time which can be coming from different manufacturer’s devices, there should be one common protocol for communication and that is OPC. It was in 1996 when OPC was founded to share data of different manufacturers so they can talk to each other efficiently. In our daily usage of computers and laptops, there is one method DDE (Dynamic Data Exchange) which is used to communicate between internal applications. With the DDE method, you can only communicate between two PC or laptops. Due to this limitation, this method can’t use in process control which led OPC t...

 OPC (Object Linking and Embedding for process control) was released in 1996 by the OPC Foundation and was soon adopted for the interoperability of industrial systems. The name was later changed to Open Platform Communications in 2011 to broadening variations beyond Microsoft’s pioneer OPC. As a mechanism for interoperability, it is used by OPC Servers to provide data to PLC applications like HMI and Historian via OPC Clients. OPC in PLC Systems OPC Basics (Source: Novotek) Which OPC is Commonly Used in Old PLC Systems? Among the first OPC, versions to be introduced include OPC Data Access (OPC DA) in 1996, OPC Alarms & Events (OPC AE) in 1999, and OPC Historical Data Access (OPC HDA) in 2001. These three were designated as classic OPC after the introduction of OPC UA. While all three are highly compatible and preferred for old PLC systems, OPC DA stands out as the most commonly used. Classic OPC Clients and Servers send commands, requests, and data using Microsoft’s COM (Compo...