PRACTICAL STUDENT TEACHING THROUGH INTEGRATED

TRUE, VIRTUAL AND REMOTE LABORATORIES

A. Mart´ı Campoy, J. C. Campelo, J. J. Serrano, M. Alonso

Departamento de Inform´atica de Sistemas y Computadores, Universitat Polit`ecnica de Valencia, Valencia, Spain

S. Coll

Departamento de Ingenier´ıa Electr´onica, Universitat Polit`ecnica de Valencia, Valencia, Spain

Keywords:

Simulation, Virtual, Remote, Lab work, Acquisition card.

Abstract:

Currently data acquisition cards are being widely used by process control engineers. In this paper an integrated

tool supporting work on a true, virtual and remote laboratory is described. The presented techniques provide

different levels of independence from the direct access to the real system through a remote access to it or

interacting with a virtual system based on simulation. One signiﬁcant contribution, apart from the integrated

approach, is its simple use by the students since the students can move from real lab to virtual with no changes

in their work.

1 INTRODUCTION

Nowadays the programs of many engineering degrees

include subjects that provide the students with the

knowledge required to analyze control systems hard-

ware architecture. That is, how to signals coming

from a process to be controlled have to be connected

to the processor responsible for executing the control

algorithms. In this framework, these subjects devote

a signiﬁcant amount of class time to describe data ac-

quisition cards as one of the most widely used alter-

native to interface processes and personal computers.

It is important to note that the laboratories used

to teach the students in measurement and control sys-

tems require speciﬁc purpose hardware apart from a

personal computer, i.e. a data acquisition card and

some process (or an emulator) capable of being mon-

itored or controlled.

Hence, the speciﬁc needs of such subjects prevent

the students from working on their own computer at

home or even in general purpose computer laborato-

ries. This restriction signiﬁcantly limits student inter-

action with very important aspects of real world ap-

plications very common in their professional career

as engineers. Only during the time dedicated to lab-

oratory sessions the students have the opportunity to

work using equipment close to that used in real appli-

cations. Moreover, the high cost of specialized labo-

ratories further deepens this problem.

The above limitations, which have been high-

lighted by several authors during the past years,

are traditionally solved, or at least compensated, by

means of the use of simulators (also known as virtual

laboratories) and remote laboratories (Stonick, 1993),

(Shaheen et al., 1998). Also, computer use in exper-

iments greatly simpliﬁes the normally routine and te-

dious task of gathering data and facilitates the analy-

sis, creativity and development of scientiﬁc and engi-

neering skills (Barton and Rogers, 1991).

As mentioned, previous work on this ﬁeld focuses

on two different approaches: 1) virtual laboratories,

where the process under control is simulated by a

computer; and 2) remote laboratories, where a phys-

ical implementation of the process can be accessed

remotely through the Internet.

Virtual laboratory is a very powerful tool that al-

lows students to develop and check their own under-

standing of processes and experiments autonomously

before working on the real system. In addition, simu-

lation is a common technique in the design process of

many commercial products and, hence, a useful back-

ground for their work once graduated. Nevertheless,

an intensive use of simulation is not recommended

since spaces out students from the real world.

Also, when asking students, they prefer to work

in a real laboratory, considering virtual tools a good

382

Martí Campoy A., C. Campelo J., J. Serrano J., Alonso M. and Coll S..

PRACTICAL STUDENT TEACHING THROUGH INTEGRATED TRUE, VIRTUAL AND REMOTE LABORATORIES.

DOI: 10.5220/0003310703820385

In Proceedings of the 3rd International Conference on Computer Supported Education (CSEDU-2011), pages 382-385

ISBN: 978-989-8425-49-2

 2011 SCITEPRESS (Science and Technology Publications, Lda.)

complement (Torres et al., 2006). That is the rea-

son why remote laboratories ﬁnd interesting beneﬁts:

costly resources sharing with remote 24/7 access, and,

at the same time, students feel remote laboratory like

the real one (P.Lundgren et al., 2006). Finally, sig-

niﬁcant contributions in this ﬁeld are the use of real

processes with direct alumni observation such as the

integration of a true laboratory with a virtual one (Ko-

cijancic and OSullivan, 2002) or the integration of a

remote and virtual labs (Saliah et al., 1999).

In this work an step further is provided, integrat-

ing true, virtual and remote laboratories using uniﬁed

tools, making switching from lab sessions in one par-

ticular form to another one extremely easy. The re-

sult is a learning process composed of different phases

where the student ﬁrstly simulates and secondly per-

forms a real experiment on a real system.

As an improvement over previous reported tools,

where the interaction with the remote laboratories is

reduced to data gathering or visualization (Imbrie and

Raghavan, 2005), our tools allow the student to act

on the processes not only in the control actions but in

process conditions.

These features encourage autonomous learning,

which is a process that allows the student to choose

paths, strategies, tools and times to learn and practice

with what has been learned.

The rest of the paper is organized as follows. Sec-

tion 2, 3 and 4 describe the organization of the true

lab sessions, the virtual laboratory and the remote lab-

oratory, respectively. Finally, some conclusions are

drawn in Section 5.

2 TRUE LABORATORY

The real laboratories used to teach control sys-

tems and industrial computer-based automation are

equipped with personal computers and data acquisi-

tion cards, to provide signal conditioning and moni-

toring and control hardware. Once the students are

given with the basic concepts to program the data ac-

quisition cards they can use them, together with the

computers, to control real processes specially devised

to be used in the laboratory. The set of available pro-

cesses to be controlled are: a printed circuit board to

provide basic analog and digital inputs and outputs,

an articulate arm (Figure 1), a model of a room with

temperature and light control, and a model of a bridge

crane with a clam (Figure 2). The limitation is stu-

dents cannot work in advance to design their data ac-

quisition programs, verify the implementation of their

control systems nor debug their software. They have

the limited time slot provided by the subject and lab-

oratory schedules, greatly conditioning what they can

do and what they can be asked to do.

Figure 1: Laboratory equipment: articulate arm.

Figure 2: Laboratory equipment: bridge.

3 VIRTUAL LABORATORY

As stated in Section 1, the virtual laboratory allows

students to work on every lab experiment from any

computer, either at the university or at home without

requiring a data acquisition card or the physical pro-

cesses. It is based on a software tool that simulates

the different system building blocks, their interfaces

and the connectivity between them and with students

application programs. The structure of the proposed

tool is shown in Figure 3.

PRACTICAL STUDENT TEACHING THROUGH INTEGRATED TRUE, VIRTUAL AND REMOTE

LABORATORIES

383

Figure 3: Virtual laboratory tool building blocks.

• Virtual Library (VL).

This library provides a set of functions that replicates

the original ones used on the real data acquisition used

in the real lab. These functions can be used on user ap-

plications with the only difference that their execution

will operate on a virtual card. The communication

is performed through TCP/IP using sockets (Walton,

2001), (Comer, 1997).

• Virtual DAQ (VD).

The virtual data acquisition card (Figure 4) is respon-

sible for emulating the real card operation. It provides

two socket-based access interfaces, one to the VL and

the other one to the Virtual Process (VP). From the

VL side, the VD receives requests to perform write

or read operations in registers, and replies according

the internal DAQ state. Data exchanged between the

Virtual DAQ and the Virtual Library is always digi-

tal, that is, for analog inputs or outputs their value is

converted to digital according the converters included

in the real DAQ. From the VP side, VD sends val-

ues of outputs when internal registers change, and re-

ceives, asynchronously, input values as they change

in the Virtual Process. This emulates the real behav-

ior of a true daq. Data exchanged between the Virtual

DAQ and the Virtual Process is always in volts (or

amperes) because this is the outdoor side of the DAQ,

that is, the real, analog world. This allow to design

virtual processes with no knowledge about bit resolu-

tion of converters, for example, and allowing its use

with several different cards.

Figure 4: Virtual data acquisition card.

• Virtual Process (VP).

The objective of this building block is the simulation

of processes to be controlled by a user application

executing a control program. The VP simulates the

process, the transducers responsible for measuring the

magnitudes of interest and the operation of the actu-

ators used to interact with the process. The virtual

process provides a graphical interface that allows the

student to change process parameters, introduce per-

turbations, modify the transducer being used or the

signal conditioning element. For each real process

presented in Section 2, which are available in our lab-

oratory, we have designed a virtual process. As an

example, the virtual process simulating room temper-

ature and light, whose graphical interface is shown in

Figure 5, allows settings of: external ambient tem-

perature, external light received through the window

whereas the student must develop and test the control

algorithms for room temperature and light.

Figure 5: Domotic system virtual process.

4 REMOTE LABORATORY

The remote laboratory is based on a set of tools that

complement the Virtual Laboratory. The goal is mak-

ing it possible for the student to have access to the real

system through an Internet connection. Remote lab-

oratory can be accessed in two different ways, either

on-line or off-line. The block diagram of the complete

set applications developed for the Remote Laboratory

is shown in Figure 6.

• On-line Acces.

In this case the students write, compile and execute

monitoring and control programs on their local com-

puter. During the user program execution all the data

acquisition card operations are sent using a TCP con-

nection to a real card located at the laboratory and

connected to a real process. The library the student

must use to write their programs using the data acqui-

sition card is exactly the same one used for the Vir-

CSEDU 2011 - 3rd International Conference on Computer Supported Education

384

Figure 6: Remote laboratory building blocks.

tual Laboratory (Section 3). The difference now is

that the communication is performed through the In-

ternet with the Network DAQ element (ND), running

on a remote computer located in the real laboratory.

The Network DAQ block directly operates on the real

card.

A signiﬁcant contribution we included in our soft-

ware tool box for the Remote Laboratory is a mecha-

nism for the student to check the operation of a pro-

gram by directly analyzing the behavior of the real

system as he was working in a real lab. This mecha-

nism is based on two blocks based on a client-server

called Monitor. Monitor Server runs on the real lab

computer, and uses a second DAQ to monitor sys-

tem’s state. This state, and a video stream, are sent

to Monitor Client. Monitor Client receives video and

data gathered by Monitor Server, and allows student

to interact with the real process enviroment, like in

simulation.

• Off-line Access.

In order to avoid the communication delays when lo-

cated remotely the students can send their source code

through the Monitor client. The source code is then

compiled and linked with the original data acquisition

card library and run afterwards. Apart from looking

at the process behavior through the video sent by the

monitor the process evolution is stored in a log ﬁle

with time stamps that allows for an off-line analysis.

5 CONCLUSIONS

During the past two years the proposed system has

been tested with students. Before ﬁnishing the

semester the students fulﬁll a survey used as feedback

path. Their opinion has been taken into account to im-

prove the platform. In general, the students consider

very useful and easy to use the set of tools.

The job presented in this paper integrates on a

single platform three experimental: true, virtual and

remote laboratories. The system relies on a virtual

data acquisition card that provides a virtual operation

very close to the original operation with a real card.

The user only has to introduce very simple changes

in the application program to follow one approach or

another.

It could have been possible to integrate all the ap-

plications into a single one. Nevertheless indepen-

dent units have been preferred because of the follow-

ing reasons:

• Keeping closer to the real system structure makes

the students easily understand the system opera-

tion and how it has been designed.

• It has the adequate modularity for selecting a dif-

ferent data acquisition card or process.

With respect to the students methodology, they al-

ways know what version of the system they are work-

ing on, but they do not need to generate different ap-

plication programs depending on their location: vir-

tual, remote or off-line.

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