Abstract: In automatic process-control systems, the integral action term in Proportional plus Integral action (P+I) control is used primarily to prevent any continued deviations from a set-point, and concomitantly to secure a bump-less transfer from manual control to automatic control. However, there are serious set-backs when using the integral action term for level controls, due to the liability of the integral action term to cause overflows from vessels, which can result in disastrous oil-spills, when a process is on automatic control. Hence, to secure a bump-less transfer without the integral action term, an alternate method is necessary. The method advocated calls for an additional term, which has been termed as a Bump-less Transfer ‘BT(t)’ term, to be included into the control algorithm.

Abstract: In automatic control systems, the Integral action term is used primarily to prevent any continued deviation from the set-point, and concomitantly to secure a bump-less transfer from manual control to automatic control. However, there are serious set-backs when using this term. Hence, unless the control system is required to maintain a process at the exact set-point, it is preferable not to have this term merely to secure a bump-less transfer from manual control to automatic control. The present invention is a novel method of securing a bump-less transfer for proportional action controllers that prefer not to have the integral action term for level controls when the system is on continuous control, due to its propensity to cause overflows, which can sometimes lead to disastrous oil-spills. The method used calls for an additional term, which I have called as a Bump-less Transfer ‘BT(t)’ term, to be included in the control algorithm.