Monthly Archive: August 2008

Aug
28

Tips-N-Techniques (TNT) – Effect of Sample Delay on Tuning and Loop Performance

If you are interested in how sample time delay affects PID tuning and performance, you might want to check out Advanced Application Note 005. AdvancedApplicationNote005 This note provides quantitative guidelines as to what point additional sample time delay causes a noticeable deterioration in performance and excessive oscillations for a given controller tuning. Alternatively, the note …

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Aug
17

Tips-N-Techniques (TNT) – Tuning Furnace and Incinerator Pressure Loops

If the pressure set point is a fraction of an inch of water column, you have a high integrating process gain. The response is often a high speed ramp in the control region. For a waste incinerator and a phosphorous furnace I worked on decades ago, the pressure could ramp off scale in 0.2 and …

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Aug
08

Tips-N-Techniques (TNT) – Tuning Runaway Reactor Temperature Loops

The heat of reaction can raise the temperature and hence the reaction rate of exothermic reactions so fast the temperature accelerates upscale. There is a point of no return reached where the cooling rate is not enough to keep the temperature from rising. If the relief valves and flare stack are sized properly, the day …

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Aug
02

Tips-N-Techniques (TNT) – Tuning Level Loops

I thought of naming this series “Truth or Consequences” or the “The End of the Innocence.” Level loops look so simple, they must be easy to tune. Also, what is so important about level? Don’t you just need to keep the vessel from running dry or overflowing? Did you know that fast surge or feed …

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