Control engineering technical information, tutorials and documents  

Contek Systems Ltd, Aberdeen, UK

Control engineering consultant for the oil and gas industry. Process control, de-bottlenecking, compressors, slugging and control system PID tuning.

Recent press releases and other news are available here.
Contek Systems Ltd,
Shampher Cottage,
Strachan,
AB31 6NN

+44  (0)1330 850598

Try my well-known Process Identification and PID Tuning package U-Tune.

Click here for details and screenshot.

See my FREE tuning calculator.

Download here.

I have written several tutorials on the practicalities of process control.

Click here for links to our tutorials.

Check back from time to time. New articles will be added as time permits.
Note: emails can be accessed offshore - telephones can't!
Home page
Home Consultancy Products Documents Contact
Process Control Information and Documents
Documents and Tutorials from Contek Systems
Observing and analysing process data
 

There is frequently a tendency to ‘leap in’ and tune control loops regardless of the actual problem. It is very often the case that process instability has its root cause in operational or instrumentation issues rather than inadequate tuning. So the very first stage in approaching a tuning exercise is to observe the data. This article introduces the importance of collecting historical trends with sufficient resolution to enable fault-finding and process-learning. Detailed analysis at this stage may indicate that the problem is not a tuning issue at all. Read more

Download as PDF.

Split range controllers
  A very common control scheme is split range control in which the output of a controller is split to two or more control valves. This article introduces the correct way to implement split range control. Read more

Download as PDF.

High and low output select logic
  High and low output select logic is used when two controllers are adjusting the same control valve. If not implemented correctly, integral windup will result in process instability. Read more

Download as PDF.

Collecting data for controller tuning
  Depending on the control system, there are several options available for recording process data for tuning purposes. It may be possible to extract text files of trend displays from the control system which can then be converted into whatever format is required for the tuning software. Read more

Download as PDF.

Error squared controllers
  I am frequently asked to visit offshore production platforms to sort out problems with the oil export or the produced water quality where the ultimate issue is not poor control in the export or water-handling systems but due to over-aggressive level control at the reception end of the process. Read more

Download as PDF.

Tuning anti-surge controllers
  This document discusses the tuning of anti-surge controllers on centrifugal compressors, most of which are designed around standard proportional-integral controller algorithms, possibly assisted by various vendor-specific techniques to ensure that the recycle valve opens when needed. Being a PI (or PID) controller, its tuning is actually no more difficult than any other process controller. Read more

Download as PDF.

U-Tune (micro-lite) User Guide
  The user guide is included in the U-Tune (micro-lite) installation software. The document includes details on general tuning techniques and controller algorithms. PDF
   
My favourite process control books
  PID Controllers: Theory, Design and Tuning by Karl Astrom
  Multivariable Feedback Control: Analysis and Design by Sigurd Skogestad and Ian Postlethwaite
  Nonlinear Dynamics and Chaos by Steven H. Strogatz
  PID without the Math by David W St Clair
   
Products for process control
  Dataq Instruments
  MATLAB
  General Algebraic Modelling System (GAMS)
  Contek's FREE tuning calculator and other products
  Books on PID control
  Books on control engineering
   
Tutorials and other learning material
  Course Notes and Learning Resources - Process Control
  Control Tutorials for Matlab
  PID controller laboratory
  Industrial Systems and Control Ltd
   
Directories related to control engineering and oil & gas
  Read-Out Ireland's Journal of Instrumentation and Control
  The Engineers' Club - Online Resources
   
Useful internet discussion groups for control engineering topics
  control.com
  sci.engr.control
  Control Systems Engineering at Eng-Tips
   
Reciprocal links
  If you would like to add your control engineering URL to this page and would be willing to put a reciprocal link on your own site, please send an email with details to: JohnGreene@contek-systems.co.uk