Research Of OPC Specification And HMI Interface Technology

OPC (OLE for Process Control) is the application of OLE (Object Linking and Embedding) technology in process control system, including a series of standard interface specifications of industry automation. OPC is put forward to solve the communication problem between application softwares and various drives. It makes the work more efficient by separating the application software developers from the hardware manufacturers. Consequently, the repetitive exploitations are reduced in the process of integrating system. OPC specification will be a developmental aspect in process automation's communication standard in future.OPC servers use Microsoft COM Technologies to communicate with clients. Based on COM/DCOM Technologies, a set of the specifications standard about objects, interfaces and methods are defined. To understand the principle and development of COM is a necessary precondition for studying OPC. Based on a brief introduction about COM, the paper emphasizes on the implement principle of COM, and we can know clearly the relationship between OPC and COM .It can be the foundation for the further application of OPC.After studying deeply BMS (Building Management System) Communication Standard of Sanyo Electric Co., Ltd. In the paper, an OPC server based on BMS is designed by using Visual C++ porgramme language, serial programming technology, and the development toolkit of SIACON-SmartOPC. HMI interface technology is also studied properly, and this OPC server is teseted by making use of HMI software. The connection between the software of HMI and the BMS spot equipments is realized with using of this OPC server. Then the correctness of the operation of OPC server is confirmed.The result of this test shows that the OPC server can fulfill the function of allowing monitoring and control (monitoring&control) software (e.g. SCADA, HMI) to access the devices which are based on the BMS Communication Standard in a consistent manner. The OPC server realizes the seamless integration between monitoring&control software and devices, and makes it easy to integrate the Building Management System into Building Automatic Control System. Repetitive works on empoldering drivers for different vendors' devices is avoided. So the OPC server will have bright prospect in future.