PI control of level

摘要

In two items in InTech (Process Control Basics letter, June 2006; and "Mind Your Ps," August 2006), statements were made to the effect that the use of PI control for level would lead to sustained oscillation or be "doomed to failure." In both cases, the reason given was that level was an integrating process. In both cases, also, the authors were touting proportional-only for level control. I have no problem with the statement that level is an integrating process, nor do I have a problem with the use of proportional-only control for level control loops. I do have a problem with the assertion that the use of PI will always lead to sustained oscillation or failure.