Tips for New Process Automation Folks

A significant part of the challenge in understanding process control is the proper use of terms to describe the dynamics in a control loop. Communication can be greatly improved by focusing on three key terms and adding a few words to more aptly describe...

Engineers love to solve problems. If your questions are intelligent and you appear conscientious and dutiful in understanding and using the information for a solution, the office door will generally be open for you. A person can tell if you are listening...

Slow oscillations can be difficult to recognize especially when the period is beyond the typical time frame of the trend chart or there are intervening disturbances or recycle. Slow oscillations can be more detrimental to product quality because the large...

I recently encountered a control cabinet on a client’s site that had 50 valve limit switches wired to a single breaker. If any of the 50 shorted, the entire group tripped off line. Between this installation and several others like it, the technicians...

The information needed to successfully select and install instruments is spread out in articles, books, handbooks, papers, and vendor catalogs and in knowledgeable individuals who do not have the time or incentive to publish. Articles and papers tend...

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...

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...

This is one of those tips that you cannot appreciate until you have worked on a control system that did NOT have adequate messaging programmed in it. Operators want to know what is going on, and system messaging is usually their only clue. Imagine running...

In the 1970s, there was a concerted effort at the chemical company I worked for to provide extra process measurement connections throughout the plants for pressure and temperature measurement. These connections could be used as needed to help identify...

Here are the new sections on process modeling fundementals 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...

At one time, I worked in a large continuous process plant that had alarms coming in constantly. The operators could hit the “Silence” button in their sleep. We had a case where a process flow was accidently diverted to the wrong tank, and it eventually...

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. Here are steps 12-16...

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. Here are steps 6-11...

When I am in an instrument and valve repair shop, I see many more control valves than instruments, particularly with the advances in sensor technology, transmitter intelligence, and asset management systems. Valves are mechanical devices and as such require...

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. Here are steps...

This may seem like a crazy tip, but there is a lot more truth in this statement than you might realize. It’s directed to management, but a young engineer may have reason and opportunity to encourage management to do this. Concept: Simple things like strong...

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...

I became sensitized to the importance of measurement location when I found the easiest way to keep a pH electrode from fouling was to install it in a pipe with a flow velocity of 5 to 7 fps, preventing the usual 100× deterioration in the speed of response...

Over the years, I have learned a number of valuable tips, either the hard way or from my talented colleagues. Here are some points that will be extremely useful to any project manager. Concept: Successful project management requires a diverse skill set...

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...

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...

When we did process control improvements in the 1980s and 1990s, the major limitation was the lack of a reliable field analyzer. None of the plants had field analyzers on raw materials. The specialty chemicals production units had very few field analyzers...

As a project manager I am responsible for a myriad of activities, but if I consider them in aggregate I realize that they are just different manifestations of the same thing: my job as a project manager is to recognize risk and manage it. Concept: Successful...

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...

The biggest mistakes I have seen in the process industry came from trying to cut costs by not using the best technology instrumentation and systems. We tend to forget that measurements are the only windows into the process and controllers and final control...