Process Control Systems Types & Selection

Clifford T Johnson, P.E., CSE

Course Outline

The methods for assisting with determining the types of controls and/or systems that could be employed for small to large process control systems.

• Functional Description (FD)
• Process Flow Diagram (PFD)
• Piping/Process and Instrument Diagram (P&ID)
• Instrument Index (II)

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this course, the student will learn:

• Requirements for determining the best Process Control system;
• Types of process control for use in modern manufacturing facilities;
• When to use Single Loop Controls (SLC);
• What are Supervisory Control and Data Acquisitioning Systems (SCADA);
• When Personal Computer and software control applications may be considered;
• Why a Programmable Logic Controller (PLC) should be considered; and
• A new integrator APC/PAC is now in place challenging DCS and PLC vendors.

Intended Audience

The process industries, those industries where the primary production processes are either continuous, or occur on a batch of materials that is indistinguishable. For example, a food processing company making sauce may make the sauce in a continuous, uninterrupted flow from receipt of ingredients through packaging. Or batches may be produced depending on the cook kettle sizes but immediately combined and re-routed. In either case, there is no concept of a unit of sauce while it is being processed.

Process, Chemical, Industrial, and Instrument Control Engineers; consultants for or working in industries such as, but not limited to:

Many industries, such as power generation, are pre-determined to use Distributed Control Systems (DCS) because of complexity, safety concerns and the majority of analog parameters involved.

The course is not intended to cover systems that are primarily digital I/O for machine automation such as: Computer Numerical Control (CNC) or robotics.

Before you do choose a vendor ask them for a demonstration system, including controller hardware. This work upfront can save a large amount of money and lost production over the life of a system.

Review the UMV's Boiler upgrade for a typical situation that can face you. If the vendor tells can not offer this before taking training course on their product, I would continue looking elsewhere.

I have personally been in a situation where the client requested we use a particular vendor who I did not believe had a fully operational DCS system. The vendor insisted that the configuration could be done by the client, but, it turned out the vendor was not being truthful and charged an additional fee to do the configuration. The project cost over ran the estimated cost by a large amount, and it took many months of fixes to get to operate satisfactorily.

Benefit to Attendees

• Eliminates possible influences or objectives by peers of the type of control system that could be employed in upgrading older control systems and new systems.
• Allows closer scrutiny of all control systems that could be employed.
• Identifies the various types of control systems available
• Identifies control types for small sub systems and large systems
• Provides Management the opportunity to review and comment on operation and make constructive comments.
• Provides additional information for consultants and contractors that can eliminate future costly change orders.
• Provides quick start on developing instruction manuals for operations and technical personnel.

Course Introduction

The basis of this course is my personal 50 year plus experiences in designing, installing, starting up, and maintaining a wide variety of Instrument and controls in the process industries mentioned. I had been employed by Moore Products Co and Bailey Controls Co as a Sales Engineer, and Fairchild Industrial Products as Product Manager. I then moved to Lead E&I Engineer for J.E. Sirrine Engineers and Day Engineering, I retired as Principle I&C Engineer for C T Main/Parson Engineering and accepted the position as General Manager and Chief Engineer for Control Services Co. leaving them to teach instrumentation at a local community college in the Mechatronics department where I am still an instructor and advisor.  (My brief resume)

The reasons for developing this course were the discussions on the LinkedIN ISA Group discussion concerning Functional Description (FD) (date 10/14/2014). It was obvious that there was no agreement on what a FD was, let alone how it should be developed and used. If you search for FD on the Internet the result is "Functional Specification" which is NOT the same as an FD in my opinion. Thus I decided to develop this course to describe a FD as I have used it in past projects, and that it should be the very first document developed when contemplating selecting and executing a process control system for a new or upgrade to an existing system.

Course Content

This course content is in the following PDF document:

Process Control Systems Types & Selection

Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.

You may need to download Acrobat Reader to view and print the document.

Course Summary

This course was meant to provide information to engineers and management that would assist them in selecting the best control system meeting their requirements and, to me, that means starting off with a good, understandable, Functional Description of the total project, not just the controls portion of the project. Everyone should now have clear understanding of the process and the I&C professionals can develop a Functional Specification for a control system that may begin on the factory floor and reach up to top management. I hope I have provided information about the various types of controls that should be considered and allow everyone involved to get there "2 cents" in. Please don't make a decision like many firms do, because controls are not like a sock "one size does NOT fit all"

Don't forget about the cocktail party where you told a lady that you were an Instrument Engineer and she wanted to know what instrument you designed, a clarinet or tuba. 

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

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DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.

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