Split range and selective control

Split range and selective control

Structure of discussion: • Split range control • Selective control • Case study: air-fuel control application – ratio control vs. selector control • Lifelong learning

• Statistical Process Control • Feedforward and ratio control • Cascade control

• Split range and selective control • Control of MIMO processes

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1. Split range control

Reference: Marlin, T.E (2000). Process Control, Chapter 22.

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2. Selective control

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To think about selective control, we consider a process example.

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Selector types • Low selector:

• High selector:

• Median selector: The output, Z, is the median of an odd number of inputs 17

Reference: Seborg, D.E. et al. (2004). Process dynamics and control, Chapter 16. 18

3. Case study: air-fuel control application – ratio control vs. selector control

High selector example

• multiple measurements • one controller • one final control element 19

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4. Lifelong learning Books: 1. Seborg, D.E. et al. (2004). Process dynamics and control, 2nd edition, Chapter 16. 2. Marlin, T.E. (2000). Process control, Chapter 22.

Trade magazines (e.g. Control Engineering) often have web-accessible tutorial articles on aspects of variable structure control. One example of these articles is: Gerry, G. (1991). Tune loops for load upsets versus setpoint changes, Control, September. http://www.expertune.com/artcon91.html

Finally, there are many web based tutorials and discussions on the basics of variable structure control. One example: “Override control”, http://www.jashaw.com/pid/override.html

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