Control Talk Blog

The Causes and Fixes for Fast Oscillations Tips

Fast oscillations are particularly insidious because the best thing a PID controller can do is ignore them. Action taken by PID controller can do more harm than good in terms of resonance, amplification, and perpetuation leading to increased process variability and premature valve failure.

MPC Best Practices for ISA Certification of Automation Professionals (CAP) Tips

Here is a new section on Model Predictive Control Best Practices for the next edition of the Guide to the Automation Book of Knowledge that is the primary resource for the ISA Certification of Automation Professionals (CAP) Program. The following includes text that may not fit into the page allocation for Chapter 13 on advanced control. 

Fundamentals of Process Modeling for ISA Certification of Automation Professionals (CAP) Tips

Here are the new sections on process modeling fundamentals for the next edition of the Guide to the Automation Book of Knowledge that is the primary resource for the ISA Certification of Automation Professionals (CAP) Program. The following includes text that may not fit into the page allocation for Chapter 12 on process...

A Unified Approach to PID Control Steps 12-16 Tips

A unified approach to tuning has been found that enables a common and simplified method for setting PID tuning parameters. Key features can be used to eliminate the need for retuning to deal with different dynamics and objectives.

A Unified Approach to PID Control Steps 6-11 Tips

A unified approach to tuning has been found that enables a common and simplified method for setting PID tuning parameters. Key features can be used to eliminate the need for retuning to deal with different dynamics and objectives.

A Unified Approach to PID Control Steps 1-5 Tips

A unified approach to PID Control has been found that enables a common and simplified method for setting PID tuning parameters. Key features can be used to eliminate the need for retuning to deal with different dynamics and objectives.

How to Improve Setpoint Response Tips

A PID tuned for maximum disturbance rejection in a composition, temperature, and gas pressure loop will exhibit excessive overshoot in the setpoint response unless one of several PID features is used. The options are relatively easy to configure. Here we discuss performance metrics and test results.

How to Avoid a Common PID Tuning Mistake Tips

The process variable has slow decaying oscillations. Control theory text books indicate decreasing the PID gain should make the loop more stable. You decrease the PID gain. The oscillation gets worse. You decrease the gain again. The amplitude and the period get bigger. You repeatedly decrease the PID gain.

Steps to Better Process Control Tips (Part 2)

We continue this series with the steps for designing control strategies. Simple rules of thumb will be offered for setting up cascade, composition, flow, level, pH, pressure, and temperature control systems. Examples of common unit operations will help provide understanding of the steps involved.  The objective is to set the...

Steps to Better Process Control Tips (Part 1)

We start this series with the steps for the selection and installation of the field measurements and control valves or variable speed drives to enable the control system to meet plant objectives. The measurement is the essential window into the process and manipulating a flow is the essential way to...