Monitoring and Optimizing PID Loop Performance

Implementation of a Distributed Control System (DCS) provides for significant regulatory control benefits through improved control capabilities, increased system reliability, and in reducing overall maintenance costs. The DCS control and economic benefits are commonly supplemented through commissioning of advanced control applications, model-based predictive controllers, unit optimization, and enterprise planning systems. With the benefits of these various advanced control implementations largely realized in many process plants and with growing pressures on profitability, however, companies are extremely focused on improving performance and optimizing their daily operations. This focus has resulted in a recent shift to emphasizing maintenance of existing applications to sustain economic benefits. This paper will present the benefits derived specifically from one of these maintenance efforts: monitoring and optimizing PID loop performance. Starting from a discussion of the case for investing in regulatory controls, the presentation will then define the challenges and opportunities related to loop maintenance, as well as the performance metrics required for successful optimization. A strategy for integrating long-term PID loop maintenance and performance software also includes process model identification, and loop simulation and tuning optimization to achieve desired control objectives.