Experimenting Across the Atlantic

A. Selmer 1, M. Goodson1, M. Kraft1, S. Sen2, F. McNeill2, B. Johnston2 and C. Colton2

1Chemical Engineering, University of Cambridge, UK, 2Chemical Engineering, MIT, USA

Technology available and stable enough to perform complex educational experiments over the internet

The exercise, the user-friendly graphical user interface and the interactive, fast responding process were appreciated by the students

The Cambridge team are now collaborating with Siemens to set up an experiment on chemical reactors

2. Experimental Setup

3. Controller Interface

4. The Exercise

5. Evaluation

6. Current Work

Acknowledgements:The Cambridge-MIT Institute (CMI)iLabs (part of iCampus)Siemens Automation and Drives Cooperates with Education (SCE)

1. Motivation

•Process control of increased importance in industry

•Remotely controlled processes used in industry and research

•Internet-based experiments offer up-to-date technologies for remote operation

•Essential training for professional life

•Heat Exchanger

•Armfield Ltd

Figure 1. Experimental setup

Mains cold water, via a valve and flow-meter, is used for the cold water side of the heat exchanger. The hot water is pumped through a heater bath, where the heater is controlled by a PID-controller; the proportional (P), integral (I), and derivative (D) parameters can be changed via the web interface. The controller allows the user to achieve and maintain a desired water temperature

into the heat exchanger, Thi, under varying flow conditions.

The equipment is designed to run over long periods of time with minimal maintenance, and once set up by the MIT staff it could be run for the complete course with only occasional supervision. Technically, the equipment and interface performed without fault for the duration of the course (ten three-hour sessions).

Figure 2. The MIT team setting up the experiment. Sid, Clark and Faye.

The graphical user interface allows the user to change set-point temperature, hot and cold water flow rates, switch between co- and counter-current flow patterns, and set the P-, I-, and D-parameters. It also shows real time values of temperatures, flow rates, and controller output. Temperatures and flow rates are also displayed in a scrolling graph and in tabular form which is observed by clicking the “Data Table” tab, and the interface allows the user to record these data to a file for later retrieval. The charts can be re-scaled to zoom in on a particular area of interest.

Figure 3. The Graphical User Interface and the chat facility

Figure 4. The University of Cambridge team testing the interface. Markus, Mike and Anders.

The interface looks and operates in exactly the same way if it is used to control an experimental setup next to the computer or if the setup is somewhere else. On the same page as the interface is also a Java chat facility for communication between the students and between the students and the tutor. A message is typed, and after the “send” button is clicked the message is visible to all logged in to the chat facility.

Figure 5. University of Cambridge students performing the experimental part of the exercise

The new exercise is divided into three parts:

1. A few preparatory questions on control enabling the students to identify the relevant variables and to calculate control parameters from open-loop test data.

2. An experimental session with observations of a real system under P-, PI-, and PID-control, followed by fine tuning of the control parameters and testing the response of the system to disturbances.

3. Processing of data obtained during the experimental session and follow up questions penetrating deeper into the subject matter.

Questionnaires assessing:

•Usability of interface

•Group work experience

•Meeting educational objectives

•Comparison to other exercisesThe remotely controlled experiment

provided an experience of qualitative behavior of P, PI and PI D control

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The I -lab heat exchanger was a beneficial learning experience

(compared to other exercises)

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The students were satisfied with the instructions and managed to use the LabVIEW interface and chat window well.

The students very much liked working in groups of four for the experimental session and felt that they could contribute to the group. When it came to group size, the students' opinions fell into two categories: either seeing little or no reason to have smaller groups, or thinking that a smaller group would have been good.

Most agreed that the exercise provided an experience of measurements and analysis of real data and the qualitative behavior of P-, PI-, and PID-control (Figure 6).

Other exercises in the chemical engineering course are purely theoretical and performed individually. This exercise offered a change by being partly performed in a group and in providing a challenge to use theoretical knowledge to tune a real system. This was very positively received by most students (Figure 7).

Figure 6. Meeting educational objectives

Figure 7. Comparison to other exercises

Figure 8. The Siemens STEP7 operating system

•Chemical reactors

•Reaction kinetics / Residence times

•Part of exercise

•University of Cambridge/MIT/others

•Collaboration with Siemens

•Industrial hard- and software

•Industrial experience

•iLabs shared architecture

At the University of Cambridge, UK, we have developed, used, and evaluated a new exercise in Process Dynamics and Control incorporating a web-based experiment physically located at MIT.

•iCampus/iLabs

•Located at MIT•LabVIEW

•Interface - operation

•Chat - communication

•Process Dynamics & Control Course

•New exercise with experimental part

•Traditional benefits from experiment

•Expose students to industrial software

•Training in remote operation

•Communication skills

•Agreement with statements

•Likert scale, 1 - 7