Monitoring, Assessing, Tuning And Software Design Of Process Loops Based On OPC

With the development of computer, control and communication techniques rapidly, the new request on the function of industry automation software has been put forward. On the basis of gathering and processing information, advanced process control (APC) technique should be applied to industrial process, furthermore, production is optimized, and practical utility is achieved. Therefore, it is necessary to design and exploit APC software.In the practical process control system, applying advanced software technology may control process loops well, and improve product quality and efficiency, and decrease stop time. On the basis of having studied the distributed component technique, e.g.COM/DCOM, OPC (OLE for Process Control) specification is introduced, which facilitate the communication between application software and equipment driver. Combing the new trend of development of the system structure of the software, advanced software package to monitor, assess, and tune process loops based OPC specification is designed. There are five function modules that are adopting data, auto-tuning, diagnosing loops, simulating, communicating.Development, technical specification, technological advantage and its practical application of OPC, etc. are dissertated. The main framework is put forward, and all interfaces and function of modules are designed in detail in this thesis. The OPC client is exploited under Visual Basic environment communicate with OPC server through OPC automation interfaces. Nowadays, although PID control is applied widely, due to not maintaining in time, most control system performance is deteriorated. Thereby, the approach of getting maximum closed log module through analyzing and evaluating data coming from control system to assess loop performance is meaningful. Adopting relay automatic tuning method to tune controller parameters for bad loop capability has been paid attention to. At last, appropriate tuned parameters are downloaded to control system, which leads to optimal process and increase benefit. The whole softwarepackage that is equivalent to an expert system provided convenience of monitoring and tuning process loops online for the engineers.The idea which has been put forward in this thesis has many virtues, such as high openness, easy expansibility, and easy maintenance etc, besides which can realize "plus and play" function. This design idea accords with development direction of software and is of keeping ahead in this field.