Blogs

Nonlinearities Recommendations Tips

We conclude our review of nonlinearities with an overview of applications and a detailed list of simple solutions to minimize the adverse effects of this everyday problem in nearly all control loops. It is impressive how setting lambda equal to 3x the largest deadtime value helps to solve most nonlinearity problems. Lambda...

Effect of Nonlinearities Perspective Tips

Here we use the broader definition of linearity to mean constant dynamics. A linear control loop has a constant total loop dead time, constant primary and secondary time constants, and a constant open loop gain. This perspective reviews the sources of dynamics and causes of nonlinearity.

Plant Speedup Stability Tips

The speedup of a plant’s response can cause loops to go from a smooth to an oscillatory response. In actual plants, the faster rate of change of a process variable important for product quality such a temperature or composition occurs for various changes in operating conditions.

The Primary Source of Disagreement in Process Control Tips

The primary reason why there are so many and so different schools of thought about control algorithms and tuning can be traced back to one parameter in the process response. What PID tuning and what PID structure is pronounced as best and even whether PID control should be used is...

What Does a Car Collision Teach us about Process Control Tips

The use of the term "process dead time" can mislead us in terms of recognizing the many sources of dead time. Also we don't often take into effect the profound effect of the speed and the entry point of a disturbance into the process.

Equipment, Piping, and Valve Mistakes Part 2 Tips

I have dug deep into my memory to add 21 more items to the list of process, mechanical, and piping design mistakes that have made our job as automation engineers more challenging and in some cases impossible. We learn the most by our mistakes.

Equipment, Piping, and Valve Mistakes Part 1 Tips

With a little help from my friends I have come up with a list of process, mechanical, and piping design mistakes that have made our job as automation engineers more challenging and in some cases impossible. We learn the most by our mistakes.

Effect of Process Dynamics on Loop Performance Tips

Most process engineers were not taught how process and equipment design affect loop dynamics and performance. Many of the more demanding control applications are the result poor process dynamics. Automation engineers can help bridge the gap and be able to intelligently discuss how plant design is affecting plant performance.

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...

How can we provide Mechanical and Process Engineering Regulatory Control Guidance Tips (Part 5)?

In part 5 we finish with a list of my foremost best practices. These practices build on the essential concepts given in Part 3. These practices offer simple fixes in the automation system design. Major improvements in the mechanical design are also introduced.