Category: Batch Control Batch Endpoint Batch Capacity Batch Cycle Time Batch Yield PID Tuning Tips Integrating Process
Submitted by Greg McMillan on Wed, 07/22/2015 - 18:02
Batch process control can seem like another world compared to continuous process control. In batch operations, process conditions are constantly changing and control loops are going in and out of service. PID control may take a back seat to sequential scheduling of manipulated flows.
Category: Cascade Control Cascade Rule Interaction Resonance Disturbances PID Controllers PID Tuning Tips
Submitted by Greg McMillan on Wed, 04/15/2015 - 21:25
Most of the control literature focuses on minimizing the integrated absolute error (IAE) for a step disturbance, often in a linear system. In the process industry, there are many other objectives and complications that require special attention.
Category: PID Tuning Process Gain Process Dead Time Process Time Constant Tips Valves Noise Process Repeatability Measurement Repeatability
Submitted by Greg McMillan on Mon, 01/19/2015 - 16:18
Each process test will typically give a different result in the process dynamics identified and consequential tuning settings calculated. Here we look at the sources of this lack of repeatability, the implications, and what can be done to improve tuning tests.
Submitted by Greg McMillan on Tue, 01/06/2015 - 23:38
There are some simple diagnostic checks and rules of thumb on tuning adjustments that can be used to find out if there is a problem with the PID tuning and what is the solution. This guidance in conjunction with good tuning software can reduce process variability introduced or aggravated by...
Submitted by Greg McMillan on Wed, 11/05/2014 - 14:14
Before the 1990s relatively few choices in PID structure were offered. There were also various supplier specific rules as to how to set the proportional mode and integral mode tuning settings to get proportional-only and integral-only control. A different model controller may have been needed for a different structure.
Submitted by Greg McMillan on Sun, 10/26/2014 - 16:06
Not knowing the implications of the PID Form in an existing control system being migrated or the PID Form learned in a University course can cause gross errors in the tuning parameters and potential instability. The PID Form predominantly used today is not the Form in most of the controllers...
Category: Load Response PID Tuning Setpoint Response Adaptive Reset Tips Adaptive Control Auto Tuner
Submitted by Greg McMillan on Sat, 08/02/2014 - 22:13
Software for auto tuning and adaptive control provide the opportunity to identify key loop dynamics besides providing a sound fundamental and automated basis for getting the best PID settings. Presented are uses of the knowledge gained and the setup of the automation system and testing/monitoring of PID performance to get...
Submitted by Greg McMillan on Sun, 07/20/2014 - 16:38
Automating any process can yield big improvements by eliminating human error and adding repeatability and predictability. The benefits are greatest when the best technology and practices are automated, the novice is protected against mistakes, and the specialist is enabled to capitalize on creativity and expertise.
Category: Cascade Control Cascade Rule Lambda PID Tuning Rangeability Tips Ultimate Period Valve Positioners
Submitted by Greg McMillan on Fri, 03/21/2014 - 11:09
Given that cascade control loops are everywhere without much consideration as to dynamic requirements, what can we do to make the implementation effective? Here are some specifics by the way of detailed recommendations on the sequence, speed, and setup for tuning PID and digital valve controllers.
Category: PID Tuning Cascade Control Ultimate Period Tips Cascade Rule Lambda Valve Positioners Rangeability
Submitted by Greg McMillan on Sat, 03/08/2014 - 20:16
Did you know all loops today use cascade control? Do you understand how cascade control can correct for lower loop disturbances before they affect the upper loop and can make the upper loop faster? Do you know what to do to keep the system from oscillating if the lower loop...