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!!!! Homework

# Course reading for next class: Chapter 7-9 (PPC).
# Assignment due by the start of Lecture #7: [[Attach:sp3.pdf | SP3]]

You'll use your answers from Q3.1 and Q3.2 on SP3. I've included the answers to Q3.1 and Q3.2 for your reference.

* %list list-page% [[Attach:Q5.1_Q5.2_notes.pdf | SP3 Homework Notes]]

Don't forget that the first part of each homework assignment is to write a sentence or two stating the purpose of the problem and what concept is reinforced.
September 06, 2013, at 08:46 AM by 69.169.131.210 -
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Half of the class derived a FOPDT model of the process using empirical fitting techniques. The other half of the class fit used a material balance to obtain a model. A comparison of the two models is shown below:
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Half of the class derived a FOPDT model of the process using empirical fitting techniques. The other half of the class used a material balance to obtain a model. A comparison of the two models is shown below:
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'''Fig 1:''' Diagram of the Gravity Drained Tank
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'''Fig 2:''' Sequence of Valve Movements to Test Models
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The linear response is easy to fit to the data but deviates, especially during the periods that are far from the steady state values.
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'''Fig 3:''' Linear Model (FOPDT). The linear response is easy to fit to the data but deviates, especially during the periods that are far from the steady state values.
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The nonlinear response is valid over a wider range of operation.
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'''Fig 4:''' Nonlinear Model Based on a Material Balance. The nonlinear response is valid over a wider range of operation.
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Attach:tank_percent_open.png
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Attach:tank.png
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Attach:tank2.png
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!!!! Linear vs. Nonlinear Models

At the end of class we ran through an example of a gravity drained tank.

Attach:tank.png

Half of the class derived a FOPDT model of the process using empirical fitting techniques. The other half of the class fit used a material balance to obtain a model. A comparison of the two models is shown below:

Attach:tank_linear.png

The linear response is easy to fit to the data but deviates, especially during the periods that are far from the steady state values.

Attach:tank_nonlinear.png

The nonlinear response is valid over a wider range of operation.
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In practice, smart-stepping or PRBS signals for identification of models for multivariable control. For tuning of PID controllers a step, doublet, or pulse test is often preferred.
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In practice, smart-stepping or PRBS signals are used for identification of models for multivariable control. For tuning of PID controllers a step, doublet, or pulse test is often preferred.
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!!! Lecture 6 - Fitting models to data

In Lecture 4 we reviewed how to extract the Gain, Time Constant, and Dead-time from a step test. There are many situations when it is not possible or doesn't make sense to generate a complete step test.

A FOPDT model can be obtained by fitting the model to data. This allows other forms of step testing such as:

* Pulse: step up followed by step back to original value
* Doublet: two pulses in opposite directions
* Pseudo-Random Binary Sequence (PRBS): steps of varying frequency and magnitude
* Smart-stepping: optimize steps to extract the most information while keeping the process within bounds

In practice, smart-stepping or PRBS signals for identification of models for multivariable control. For tuning of PID controllers a step, doublet, or pulse test is often preferred.

* %list list-page% [[Attach:Lecture6_notes.pdf | Lecture 6 Class Notes]]

!!!! Homework

# Course reading for next class: Chapter 7-9 (PPC).
# Assignment due by the start of Lecture #7: [[Attach:sp3.pdf | SP3]]

You'll use your answers from Q3.1 and Q3.2 on SP3. I've included the answers to Q3.1 and Q3.2 for your reference.

* %list list-page% [[Attach:Q5.1_Q5.2_notes.pdf | SP3 Homework Notes]]

Don't forget that the first part of each homework assignment is to write a sentence or two stating the purpose of the problem and what concept is reinforced.