Developing a Scalable and Reliable Online Laboratory for Engineering Education Using NI Products

Author(s):
Ling Keck Voon - Nanyang Technological University
Duan Bing - Nanyang Technological University

Industry:
University/Education

Products:
Compact FieldPoint, Measurement Studio, FieldPoint, LabVIEW,

The Challenge:
Implementing a scalable, reliable online laboratory (OnlineLab) system for enhancing e-learning at the Nanyang Technological University for engineering education.

The Solution:
Using National Instruments DAQ, FieldPoint, Measurement Studio, and LabVIEW graphical development environment to set up an OnlineLab for undergraduate students to conduct real experiments rather than Web-based simulation through Internet.

Developing the Online Laboratory
The mission of the NTU e-learning initiative is to provide online services in the areas of instructional design, staff development, and support for the use of emerging technology and tools for education. As part of the e-learning system, the OnlineLab extends the idea of online education to laboratory lessons. To simplify implementation and to connect a wide variety of real apparatus to the current e-learning framework at NTU, we integrated DAQ, FieldPoint, Measurement Studio, and LabVIEW as development tools.

For the OnlineLab, we specifically offer:

• OnlineLab framework (e-Learning framework)
• Web-enabled experiments (learning objects)

Just like a real laboratory, we can locate one or more experiments in the same OnlineLab, and students access these experiment setups. In our schema, the OnlineLab framework provides the specification for serving a variety of online experiment requests and live-data feedback of experiment status to client machines. In a typical Web-enabled experiment, students might connect physical apparatus, such as a coupled tank, inverted pendulum or solar tracking apparatus, to a controller such as FieldPoint or a PC running LabVIEW application to support a TCP/IP function. In the OnlineLab system, we treat the coupled tank connected to FieldPoint or PC running LabVIEW application through DAQ as the experiment. To share laboratory resources and reduce development time, the OnlineLab framework provides the uniform and standard platform for hosting a variety of experiments. We use TCP sockets to connect the controller to the OnlineLab framework in a plug-and-play manner.

Implementation
The OnlineLab framework supplies a variety of apparatus and the platforms for all students to conduct real experiments remotely through the Internet. For the purpose of compatibility with e-learning specification, the design of OnlineLab framework inherits features from NTU’s current NTU’s e-learning framework. Furthermore, we have added some new modules for managing online experiments. Specifically, we have developed the apparatus management and report submitting/marking APIs. Students can use the Queue daemon module for orderly access to the real apparatus on a first-come-first-server basis, with a time-out feature. The existing e-learning system handles tasks, such as user account management, online courseware deployment, metadata tagging, data tracking, and learner progress reporting.

To simplify system development, we have separated the implementation of Web-enabled experiments into two parts controller and user interface (UI). Students can use the controller, which resides on either a FieldPoint or a PC running LabVIEW, to perform the actual real-time control tasks. The UI, which resides on the online server machine, serves as the control panel for remote users. The reasons of separating these functions include:

• It simplifies the design of a complicated experiment
• It makes the system highly modular
• The professor can concentrate on the implementation of algorithm for controller, while an instructional developer can focus on the user interface (UI).

The controller contains five main functions:

• Read_cmd.VI reads control parameter string from the OnlineLab server through the TCP connection
• Cmd_cvt.VI converts string to control parameter
• Act.VI generates control signal via different algorithm such as Manual, On/Off, PID, MPC
• Log.VI collects experiment data
• Send_data.VI sends experiment data to the OnlineLab server for plotting and analyzing

We have separated other tasks, such as user interfaces and report generation engines, from the controller. We will development and integrate control algorithms using the Act.VI. We needed to assign a unique IP address to the controller for exchanging data with a TCP socket connection with the online server. This modular design minimizes the development time when we add new algorithms.

Interactivity is essential for the students to execute an experiment remotely. To provide the UI for student to conduct the experiment using an Internet browser, we have created an ActiveX UI corresponding to the Controller, using Measurement Studio 6.0.

Students can use a control panel with clear control diagram to perform several different control methods, such as Manual Control, On/Off, PID, MPC, and PRBS test. The experiment data is plotted in two charts, which provide dynamic and continuous monitoring of the status of the Coupled Tank, including set point, water level, and pump voltage during the whole experiment.

As mentioned above, students can use the UI to control panels and charts. Different controllers can share the same UI if they have the same reading and converting module for control parameter. This means we can interchange FieldPoint with the PC running LabVIEW application in our system to achieve the same result.

Additionally, students can download all data collected by the Online Server for further analysis after the completed experiment. Thus, with DAQ, FieldPoint, Measurement Studio, and LabVIEW we can achieve a scalable and reusable Online Laboratory in a time-saving and cost-effective manner.

Further Development with the OnlineLab
Upon the construction of the OnlineLab framework, we will develop more experiments, including inverted pendulum, solar tracking apparatus, GPS receivers and 3D images process, and add them into the OnlineLab family. Comparing with previous work on this area, the new Online Laboratory system provides:

• Highly modular design and implementation methods
• Scalable and reusable OnlineLab infrastructures
• Flexible and powerful e-learning services

Upon the successful implementation, we have found that, from hardware to software, National Instruments FieldPoint and DAQ hardware and Measurement Studio and LabVIEW software provide a perfect solution for scalable and reusable applications.

For more information, contact:
Duan Bing
Project Officer
Nanyang Technological University
Automation Lab, NTU, EEE, S1-B4C-10, Singapore 639798
Tel: 0065 67904550
E-Mail: ebduan@ntu.edu.sg

or

Ling Keck Voon
Associate Professor
Nanyang Technological University
School of Electrical and Electronic Engineering
S2-B2A-22, Singapore 639798
E-Mail: ekvling@ntu.edu.sg

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