1. ChE 433 D(  V )PCL Highlights What I want you to take away on a 3 x 5 card

2. Define the control problem … - Macro vs. Micro - Deterministic vs. Heuristic - Self-regulating and non self-regulating - Dead time, how much compared to lags - Linearity, is the process linear with load?

3. Accuracy vs. Repeatable

4. Errors accumulate √   2

5. Hysteresis and Dead band – Did your valve move, how much?

6. Filters, only when necessary! - Do not use digital filter for electrical noise! - 3 second filter time constant for hydraulic noise - Filters add control lag

7. Make that signal linear!

8. Linear signals allow the same controller settings for all loads! Determine L, compensating equation is 1/L

9. Controller modes, tuning … - Why not use proportional only? - PI will work most of the time - Consider Lambda, reset setting cancels the combined process lag - Ultimate period method more accurate than graphical method

10. Tuning … - Bode plot shows minimum gain at critical frequency

11. The operator might not like your idea of good control!

12. Lambda Tuning Set the reset value to cancel the total process time constant.

13. Lambda Tuning; The Reset cancels the total process time constant

14. Feedfoward … If you can measure the disturbance, consider using the measurement as a “feed forward” signal to anticipate the disturbance

15. Flow Control … Low gain, due to noise, fast reset, no rate Equal percentage valve trim

16. Level Control … Will proportional only do? Regulating or non-self regulating?

17. Pressure Control … Regulating or non-self regulating? Gas or liquid? That is compressible? Liquid pressure can be tuned like flow loops

18. Temperature Control … Heat transfer depends on velocity Set point profiles for batch

19. Temperature Control … Sensor placement

20. Temperature Control … For steam service, condensate removal

21. Multivariable Control … Can Tuning remove the interaction?

22. Multivariable Control … Relative Gain Array shows interaction Model control