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Remote Operation and Control of Traditional Laboratory Equipment

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Remote laboratory architecture

Author(s):
Unai Hernández - University of Deusto
Javier García Zubía - University of Deusto
Ingvar Gustavsson - Blekinge Institute of Technology, Sweeden

Industry:
University/Education

Products:
LabVIEW

The Challenge:
To allow the students involved in an electronics subject to build their own circuits and test them as they were in a traditional laboratory, but doing it in a remote way.

The Solution:
On one hand, a switching matrix allows the different components to interconnect, and the instruments placed in the NI PXI-1042Q make it possible to test the circuits. On the other hand, a Web application allows the students to interact with this hardware from their home through the Internet.

"With this software, the switching matrix and the instruments in the PXI are controlled according to the specification of the circuit that the student has just built in the Web session."

One of the goals of modern universities is to decentralize part of their activities, giving students more freedom to organize their own schedules. In this sense, the European Union now faces a new challenge: the reforms introduced by the Bologna Conference. In this new educational framework, students will have more freedom to organize their time, which will result in loosely supervised schedules that will complicate running the labs. Using a remote laboratory, the students can access hardware equipment through a Web interface to program, control, and observe the evolution of their actions in real time. Thus, the student can realistically work with hardware from his home, or any other place, without the layer of abstraction that simulations add. These laboratories supported by Web technology add numerous benefits to lectures, students and educational institutions. Table 1 shows the most significant benefits [1].

Students

Lecturer

University

 

•          It facilitates the theoretical-practical comprehension of the subject

 •          Students feel more motivated when controlling the experiments according to their own devises and initiatives

 •         Students select their own schedule and program their practices.

 

 

 

 

 

•          It allows the lecturer to contact the students in an autonomous way.

 •          It can include the control of an experiment in a theoretical class.

 •          It reduces the number of groups in practical lessons.

 •          It allows the lecturer to set up a system in remote control.

 

 

•          The laboratory is open seven days a week twenty four hours a day.

 •          Smaller laboratories with less investment in equipment.

 •          Less specialized staff, eliminates risks

 •         The throughput of the devices increases to a maximum

 

 

Blekinge Institute of Technology in Sweden has opened a local traditional electronics laboratory for remote operation and control [2]. It is equipped with a unique virtual interface enabling the students to recognize on their own computer screen the desktop instruments and the breadboard they have already used in the local laboratory. The physical breadboard has been replaced by a circuit-wiring robot which is remotely controllable, i.e. a switching relay matrix. The laboratory is used in regular courses for students on campus as well as for distant learning students in Sweden and abroad. For example, the next year, the University of Deusto in Spain will use this remote laboratory in one of the Industrial Engineering subjects.

 Software Organization

The software solution is divided in four different parts (Fig. 1). A Web interface handles administration, user admission and resource scheduling. There is an experiment client through which the users can control the experiments. The measurement server is responsible for handling the experiment requests from the experiment clients. Finally, there is the equipment server, which is a standalone equipment controller, handling the low level instrument interfaces. In the user interface, the student has all the possibilities as if he were placed in the traditional laboratory: a breadboard to interconnect the components and the instruments (Fig. 2), a component box and all the front panels of the available instruments.

A typical session consists on performing measurements and viewing the results. When a user makes a measurement, the experiment client takes the settings from all the instrument modules and compiles them into a measurement request. This request is subsequently sent to the measurement server, which returns a response that can be read by the instruments to update their displays. The measurement request and response is transmitted using the experiment protocol, an XML based protocol describing what settings and functions each instrument type can perform, independent of hardware manufacturer. This makes it possible to implement new modules, for example imitating an instrument that is not available in the current instrument set.

Hardware Organization

The hardware side is controlled by the equipment server (Fig. 1). The server software is written in NI LabVIEW and the instrument drivers are IVI (Interchangeable Virtual Instruments) compliant. With this software, the switching matrix and the instruments in the PXI are controlled according to the specification of the circuit that the student has just built in the Web session.

The equipment server is in charge of hosting the instrument hardware for electronics experiments, plus a relay switching matrix. The switching matrix is the card stack on the top of the PXI chassis in Fig. 3. It is possible to wire a circuit with up to 16 nodes by engaging a number of relays in the current matrix.

The card stack contains three types of board: one for components, one for connecting instruments and another one for the power supply. A component board comprises 10 sockets for components with two leads, two 20-pin IC sockets for components with more pins than two, and 10 double-pole single-throw relays. One oscilloscope and two function generators or a DMM can be connected to an instrument connection board. The nodes passing all boards can be connected to sources, instruments, and/or components mounted in the sockets via relay switches. The instruments that the students can use to test their circuits are placed in the NI PXI-1042Q chassis: NI PXI-4070 (DMM), NI PXI-5112 (oscilloscope), NI PXI-5412 (function generator) and NI PXI-4110 (power supply).

Conclusions

As with all remote laboratories, this system does not want to replace the traditional laboratory, but rather use it is a complement to the learning tools for the students to fulfill the practical lessons requirements in a subject related to electronics. In this way, the students can access to the laboratory as many times as necessary and therefore, allowing them to practice the exercise before doing it in the hands on lab. Testing concludes that students who used this remote laboratory before the real one, where they are in front of the real breadboard, components and instruments in the traditional laboratory, they felt more self-confident and performed better.       

This system is involved in the VISIR project [2], headed by the professor Ingvar Gustavsson from the Blekinge Institute of Technology (Ronneby, Sweden) and with the collaboration of the University of Deusto (Bilbao, Spain) and the FH Campus Wien (Wien, Austria).   

References

[1] J. García Zubía, U. Hernández. “WebLab-GPIB at the University of Deusto” REV 2007, Porto (Portugal), June 2007

[2] I. Gustavsson, J. Zackrisson. “An Overview of the VISIR Open Source Software Distribution 2007”. REV 2007, Porto

Author Information:
For more information on this Case Study, contact:
Unai Hernández
University of Deusto

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