Assessment of Ziegler-Nichols tuned loops using control performance monitoring indices

Most control and process engineers face a large amount of complex processes found in industry and they usually need tools for assessing their performance. This paper deals with the assessment of real industrial control processes of a pilot process plant using standard control performance monitoring indices. The control loops have been tuned using the well-known Ziegler-Nichols method. A comparison between the implemented indices with those based on the APC (Advanced Process Control) PCS7 library is performed¹.