Open Learning Approach with Remote Experiments
518987-LLP-1-2011-1-ES-KA3-KA3MP
Multilateral Projects
UNIVERSITY OF DEUSTO
Annex: VISIR Remote
Laboratory
OLAREX project report
Olga Dziabenko, Unai Hernandez
The document provides the main principle to work with remote Laboratory VISIR. The VISIR was
designed for the teaching students to build the electrical circuits for different levels of knowledge:
beginners, advance and experts
This work has been performed within the project "OLAREX: Open Learning Approach with Remote
Experiments", 518987-LLP-1-2011-1-ES-KA3-KA3MP. This project is funded with support of the Lifelong
Learning Programme of the European Union. All here provided information and documentation reflects the
views only of the authors, and the Commission cannot be held responsible for any use which may be made of
the information contained therein.
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Document revision history
REVISION
Javier Garcia Zubia
DATE OF RELEASE
PURPOSE
Revision of diagrams and notifications
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Content
1
INTRODUCTION ........................................................................................................................................ 1
2
OBJECTIVES .............................................................................................................................................. 2
3
REQUIREMENTS ........................................................................................................................................ 2
4
EXPERIMENT IN VISIR ............................................................................................................................... 3
4.1
HOW TO START ........................................................................................................................................ 3
4.2
HOW SET UP COMPONENTS IN THE CIRCUIT .................................................................................................... 5
4.3
LABORATORY EQUIPMENT .......................................................................................................................... 6
4.3.1
Digital Multimeter........................................................................................................................ 6
4.3.2
DC Power ...................................................................................................................................... 7
4.3.3
Function Generator ...................................................................................................................... 8
4.3.4
Oscilloscope................................................................................................................................ 10
4.4
4.4.1
4.5
4.5.1
5
SIMPLE MEASUREMENTS .......................................................................................................................... 10
Exercises ..................................................................................................................................... 14
CIRCUITS WITH ALTERNATING CURRENT ...................................................................................................... 14
How to link the laboratory equipment ....................................................................................... 16
Q&A: QUESTION AND ANSWER .............................................................................................................. 18
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List of Figures
Figure 1: VISIR switching matrix connected to laboratory equipment .................................................................... 1
Figure 2: User Interface for the remote experiment............................................................................................... 2
Figure 3: Login in Moodle area ............................................................................................................................... 3
Figure 4: VISIR experiments in WebLab-Deusto ..................................................................................................... 3
Figure 5: Reserve the experiment ........................................................................................................................... 4
Figure 6: Screen for selection of the laboratory equipment ................................................................................... 4
Figure 7: Three area of the interface ...................................................................................................................... 5
Figure 8: Library of components for the circuit ...................................................................................................... 5
Figure 9: Industrial multimeters ............................................................................................................................. 6
Figure 10: VISIR multimeter.................................................................................................................................... 7
Figure 11: VISIR DC Power ...................................................................................................................................... 7
Figure 12: Control knob of DC Power ..................................................................................................................... 8
Figure 13: Function generator: Frequency displayed ............................................................................................. 8
Figure 14: Function generator: Amplitude displayed ............................................................................................. 9
Figure 15: VISIR – Oscilloscope .............................................................................................................................. 10
Figure 16: Checking the components ................................................................................................................... 11
Figure 17: Three resistors (R1,R2,R3) connected in series .................................................................................... 11
Figure 18: VISIR - Three resistors (R1,R2,R3) connected in series ......................................................................... 12
Figure 19: Measuring the Voltage diagram .......................................................................................................... 12
Figure 20: VISIR - measuring the Voltage .............................................................................................................. 13
Figure 21: Connection Ground in the VISIR for +25V output. ................................................................................ 13
Figure 22: Measuring the Current diagram ........................................................................................................... 14
Figure 23: VISIR - measuring the Current .............................................................................................................. 14
Figure 24: Circuit diagram with alternating current ............................................................................................. 15
Figure 25: VISIR - Circuit diagram with alternating current .................................................................................. 15
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Figure 26: VISIR – Error alert/message ................................................................................................................. 17
Figure 27: VISIR – Oscilloscope .............................................................................................................................. 17
Figure 28: VISIR – signals from Channel1 and Channel2 ....................................................................................... 18
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List of Tables
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1
Introduction
VISIR is not a simulation, it is real experiment on real equipment!
The VISIR (Virtual Instrument Systems in Reality) is an initiative developed by the team of Prof. Ingvar
Gustavsson, Blekinge Institute of Technology (BTH, Sweden). The hardware and software
architecture of the remote laboratory use for developing basic analogue electronics experiments
remotely.
VISIR allows students to create electronic circuits via Internet and experience with them. Because of
this feature real experiments can be performed over WebLab from anywhere with access to Internet.
For example, at WebLab-Deusto students can exercise with FPGAs, CPLDs, PICs and laboratory of
telecommunications instrumentation.
The big advantages are
(1) VISIR is accessible 24 hours a day and 7days in week
(2) Experiment/laboratory work is performed by building physical circuits and measuring the
signals with the same laboratory equipment: function generator, oscilloscope, multimeter
and power supply.
The VISIR currently is used for teaching in 7countries such as Austria, Sweden, Portugal, Spain, India,
etc.
In this unit we will give you an idea how from web interface you can control the equipment remotely
(¡Error! No se encuentra el origen de la referencia.)
Figure 1: VISIR switching matrix connected to laboratory equipment
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The switching matrix is responsible for physically building the circuit and connecting it to laboratory
equipment such as function generator, oscilloscope, multimeter and power supply.
Where can be built the circuit?
Well… that is what the software architecture is responsible for. ¡Error! No se encuentra el origen de
la referencia. shows the VISIR user interface. As you see it's a breadboard that usually used in the
scientific laboratory for creating the electrical circuits.
Figure 2: User Interface for the remote experiment
NOTE: Best way to learn is playing with all buttons. Do not be afraid you activity will not break
anything!
2
Objectives
To get knowledge and experience to work with remote laboratory VISIR for building electrical
circuits
To introduce laboratory equipment such as multimeter, direct current (DC) Power,
Oscilloscope, and Function Generator
3
Requirements
(1) Good quality Internet Connection;
(2) Flash player. If you do not have on your computer, please install it from the website
http://get.adobe.com/flashplayer/?promoid=JOPDD ;
(3) Any web browser e.g. Chrome, Firefox, Internet Explore. VISIR remote experiment is
available over Smartphone with Android OS;
(4) MOTIVATION
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4
Experiment in VISIR
4.1
How to start
There are two options to login to VISIR:
(1) OLAREX Moodle (¡Error! No se encuentra el origen de la referencia.)
(2) Website, provided you by WebLab-Deusto team (¡Error! No se encuentra el origen de la
referencia., ¡Error! No se encuentra el origen de la referencia.)
Click on the “Run Experiment” at Moodle or on the button “Reserve”. On the screen (¡Error! No se
encuentra el origen de la referencia.) the laboratory equipment that can be chosen to perform the
experiments is presented. The default configuration of equipment appears. In the training we will use
this configuration. In order to start the button 'Done' should be pushed.
Figure 3: Login in Moodle area
Figure 4: VISIR experiments in WebLab-Deusto
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NOTE: Because of its different implementations there are different accesses to VISIR. The two main
options are VISIR and LXI-VISIR: VISIR is used for AC circuits with diodes, capacitors and oscilloscope
while LXI-VISIR is used for measuring voltage and current in DC circuits with resistors.
Please follow the instructions provided on the OLAREX Moodle platform for your connections to VISIR
remote laboratory.
Figure 5: Reserve the experiment
Figure 6: Screen for selection of the laboratory equipment
On the ¡Error! No se encuentra el origen de la referencia. the user interface – the breadboard is
presented user. It consists of three parts:
(1) Area of Components, where the components that we will use in each practice/experiment
appears
(2) Area of Circuit Design, where components will be placed and linked to the equipment
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(3) Area of Instruments, where the equipment will be configurated and used for measurements.
Figure 7: Three area of the interface
4.2
How set up components in the circuit
The set of corresponding components for building the circuit is available in a library of components.
Where can user of laboratory (further user) get the components?
Figure 8: Library of components for the circuit
In order to open the library of the components that are available for the experiment the user should
click on the button “+” on the remote lab interface. This button is marked on the ¡Error! No se
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encuentra el origen de la referencia. by number 1. The library of components, which is marked on
the ¡Error! No se encuentra el origen de la referencia. by number 2, will appear in pop-up window
format. The list of available components includes their graphical representation, description e.g.
code or series of diode, and their values, such as resistance and conductivity. In order to choose the
components for the experiment the user should click on the graphic presentation of the component.
Chosen component will be appeared in area marked on the ¡Error! No se encuentra el origen de la
referencia. by number 3. If two identical components, e.g. resistors of 1K of value are required for
the circuit, this component - in our case on the 1K resistor - should be clicked/chosen twice in the list
of the Library of components. When all components required for experiment are selected, the user
should click on the button “Close” on the library of the components window.
The library will close, but the user can add components to the experiment whenever she/he wants.
Once the user has all components in the area 3, she/he can start building the circuit.
Before we will start to build the circuit, the laboratory equipment (the instrumentation) that applies
in the laboratory´s work will be presented.
NOTE: The number of components in the Library of components - area 2 is not fixed. Depends on
each VISIR experiment implementation more resistors, or capacitors, or inductors, etc. can be
integrated.
4.3
Laboratory Equipment
4.3.1 Digital Multimeter
A multimeter or a multitester, also known as a VOM (Volt-Ohm meter), is an electronic
measuring that combines several measurement functions in one unit. A typical multimeter includes a
measure of voltage, current and resistance.
Some of the typical industrial digital multimeters are presented on the ¡Error! No se encuentra el
origen de la referencia.. It gives an output in numbers on a liquid crystal display.
Figure 9: Industrial multimeters
On the ¡Error! No se encuentra el origen de la referencia. the diagram of VISIR multimeter is
displayed. The diagram shows switched parameters of multimeter.
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Figure 10: VISIR multimeter
The central knob has lots of positions and the user must choose which one is appropriate for the
measurement she/he wants to make.
4.3.2 DC Power
The DC Power in VISIR (¡Error! No se encuentra el origen de la referencia.) is power supply, which
delivers 0 to ± 25 V outputs rated at 0 to 1 A and 0 to +6 V output rated at 0 to 5 A.
Figure 11: VISIR DC Power
The voltage and current of each supply can be adjusted independently from the front panel. Using
the front panel keys and the control knob, the user can adjust the voltage and current of a selected
output. From the front-panel VFD (vacuum-fluorescent display), the user can monitor actual values of
output voltage and current (meter mode) or voltage and current limit values (limit mode).
In order to set the voltage and current from the front panel, the user should use the voltage/current
adjust selection key
and adjust selection keys
. In the VISIR the voltage mode is set up by default. Pick on the meter
required supply value. The power supply has restriction
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the meter and adjust selection keys +6V: 0V - +6V with max 0.5A; for +25V: 0V - +25V with max 0.5A;
and for -25V: 0V - -25V with max 0.5A. The resolution selection keys
are used for moving the
blinking digit to the appropriate position. Change the blinking digit to the desired value user can by
using the control knob –wheel (¡Error! No se encuentra el origen de la referencia.).
Figure 12: Control knob of DC Power
NOTE: Depending on the VISIR implementation, not all the DC powers can be available at the same
time. For example, now in UDeusto, the -25V is not available. Please follow the instructions provided
in the laboratory assignment.
4.3.3 Function Generator
Function generator is a handy gadget that generates waveforms. Using this device the user can
generate sine waves, square waves, triangle waves etc. of varying frequencies and amplitudes.
In the VISIR we use the HP 33120A function generator (¡Error! No se encuentra el origen de la
referencia.) with frequencies up to 15 MHz. The amplitude and offset of these waveforms may be
controlled easily. The HP 33120A can supply a positive and negative DC voltage, which can be useful
in experiments as well.
Figure 13: Function generator: Frequency displayed
Below we will present some function of the generator:
(1) Function / Modulation keys
: Using this keys the student can
select a sine, square, triangle, ramp, or arbitrary waveform.
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(2) Menu operation keys
, arrow keys allow to edit individual digits:
increments and decrements the flashing digit and
right and to the left.
moves the flashing digit to the
(3) Waveform modify keys
allow to choose Frequency display (¡Error! No
se encuentra el origen de la referencia.) or Amplitude display (¡Error! No se encuentra el
origen de la referencia.)
(4) Control knob –wheel
and the arrow keys (2) modify the displayed
number on the screen of the function generator.
Figure 14: Function generator: Amplitude displayed
NOTE: The maximum voltage for the VISIR experiments is 10 Vpp. Please restrict the voltage value
for your laboratory practice.
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4.3.4
Oscilloscope
Figure 15: VISIR – Oscilloscope
NOTE: Keep in mind that AutoScale function does not exist on the VISIR oscilloscope, and volts/div
and sec/div should be adjusted manually.
The function of the oscilloscope according the areas on the Figure 15:
(1) Horizontal controls: select sec/div and horizontal position of the signal
(2) Run controls
(3) Trigger controls: LEVEL - trigger level selection; EDGE - selected edge (increasing and
decreasing) and trigger channel (1 or 2)
(4) Vertical Inputs – Chanel control: select volts/div; vertical position of the signal; the two
buttons (1 and 2) indicates whether the channel is ON
(5) This line normally contains automatic measurement and cursor results, but can also display
advanced trigger setup data and menu information (signal frequency, amplitude, period,
etc.).
(6) Measure keys: Quick measurements and Cursor provides selected channel measurements
The top line of the display contains vertical, horizontal, and trigger setup information.
As in real oscilloscopes, the vertical and horizontal arrow keys can be used to obtain measurements
on the signals.
4.4
Simple measurements
At first we will integrate, for example, resistors on the VISIR breadboard.
Once the components (in our case the bunch of the resistors) that we will use in our implementation
are chosen we should drag them on the area of circuit design and connect them according our circuit
schemes. The selected components will appear at the area of components (¡Error! No se encuentra
el origen de la referencia.). If user wants to remove a circuit component, she/he has to drag it back
to the area of components.
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The user can check the value or characteristics of selected component by moving the mouse over it,
at the right bottom of the breadboard the description is showing (¡Error! No se encuentra el origen
de la referencia.).
Figure 16: Checking the components
On the right side of the breadboard, the user can find the "wires" to connect the various components
together. For example, the different colours can be chosen to distinguish the line power ground. A
wire/cable in circuit can be eliminated simply by selecting it and pressing the delete key.
Example: Design three resistors 1k each connected in series and measure the resistance (¡Error! No
se encuentra el origen de la referencia.).
Figure 17: Three resistors (R1,R2,R3) connected in series
As you know, the equivalent resistance of resistors connected in series is the sum of their
resistances: Requivalent=∑ Ri. That is, in our case R=R1+R2+R3
Let we will design the circuit provided on the ¡Error! No se encuentra el origen de la referencia.. The
multimeter (DMM on the user interface of the VISIR) implemented in this application is the same as
you use in the real lab and is connected in circuit in the same way (¡Error! No se encuentra el origen
de la referencia.). Here we will measure the resistance value.
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Figure 18: VISIR - Three resistors (R1,R2,R3) connected in series
NOTE: (1) Only the holes in each column are connected together in one section as shown on the
Figure 18. (2) The color of wire is random and does not provide any meaning.
Let we fill out the provided below a chart. Here we will measure the only resistance value. In order to
get the information on the display of multi meter, the user should click on the Multimeter button,
choose by the central knob-wheel the
R1
Analytical , according the Requivalent=∑
1k
Using VISIR
parameter and click on the “Perform Experiment” button.
R1+R2
R1+R2+R3
2k
3k
Ri
Let we design the next circuits and measure the Voltage and Current
Figure 19: Measuring the Voltage diagram
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On the ¡Error! No se encuentra el origen de la referencia. the schema (Figure 19) will be presented
in the VISIR environment where the places of the connection of DC Power (in our case, it is +6V) and
Multimeter (DMM on the Figure 20) are marked by red colour. In order to provide +6V in the circuit
the user should choose the button “DC Power” on the interface and set the voltage (see 4.3.2).
Figure 20: VISIR - measuring the Voltage
ATTENTION: Do not forget to set voltage on the DC Power before measurement.
The multimeter will show the value closed to +6V
.
If you would like to use the voltage value more than +6V, you should use +25V button on the DC
power Supply and provide ground as shown on the Figure 21. In this case, as with real
instrumentation, you should connect GND with COM.
Figure 21: Connection Ground in the VISIR for +25V output.
In order to measure the current in the circuit the diagram presented on the Figure 22 should be built
with the VISIR (Figure 23).
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Figure 22: Measuring the Current diagram
Figure 23: VISIR - measuring the Current
4.4.1 Exercises
Design the provided circuits in VISIR, count them analytically and compare what you get with remote
laboratory. Fill the results in the Chart.
Circuit
Analytically
VISIR
The user can design own circuits using available components of the VISIR.
4.5
Circuits with Alternating Current
Look again on the VISIR interface, each side of the breadboard has the connections to power supply
(DC Power), function generator, oscilloscope, multimeter (DMM) and ground correspondently.
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We will perform the follow circuit simulation (¡Error! No se encuentra el origen de la referencia.):
Figure 24: Circuit diagram with alternating current
The components and laboratory equipment that we will use and implement are:
–
–
–
–
–
Diode 1N4007
10k resistor
Capacitor 10uF
Function Generator
Oscilloscope.
Now we place the components in the area of the circuit design matching with the circuit diagram
(Figure 24)and taking into account that only the holes in the same column are connected together
(¡Error! No se encuentra el origen de la referencia.).
Moving mouse over the components you will get their value, label and characteristics. The
parameters are demonstrated at the right site of the bottom of the breadboard.
Figure 25: VISIR - Circuit diagram with alternating current
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NOTE: 1. The cathode of the diode and resistor are connected because we put in the same column.
2. The cathode, the positive terminal resistor and capacitor are connected thanks to the
green wire.
3. The resistance and the negative terminal of the capacitor are connected together (yellow
wire) and linked to earth view of the circuit by black wire.
4. If press the”Reset” button all components return to the area of components.
4.5.1 How to link the laboratory equipment
We should place the function generator and the oscilloscope.
NOTE: The funcionl generator must be connected to the anode of the diode.
The oscilloscope has two channels. We can put each of the channels where we want. In order to see
a difference between input and output we will place the channel 1 (CH1) on the input and channel 2
(CH2) to the output.
On the (¡Error! No se encuentra el origen de la referencia.) the made connections between the
instrumentation and the circuit are presented:
1. The blue wire connects the function generator with the anode of the diode, as indicated by the
circuit (Figure 24). The ground is not needed because internally unite the grounds already joined.
2. The red wire connects the input to channel 1 of the oscilloscope.
3. The brown wire will be used to view the output signal on channel 2 of the oscilloscope.
We now need to configure the instruments.
First the function generator. Click on the button "Function Generator". The function generator will
appear (¡Error! No se encuentra el origen de la referencia.).
To modify the value of the frequency, amplitude or offset, we indicate the digit you want to change
by Menu operation keys (4.3.3). The selected digit will be flashing on the display screen in green.
Example. The circuit of Figure 23 shows that the signal is 50Hz and 10 Vpp (the maximum we can get
the function generator). To enter the frequency:
(1)
(2)
(3)
(4)
click the button “Freq”,
select first 0 decimal by the operation keys.
decrease the value 100Hz by the control knob- wheel.
Move one digit to the right and set 50Hz by the control knob.
To adjust the signal of the amplitude:
(1) click the button “Ampl”,
(2) select the 10Vpp by the control knob. The maximum amplitude on this device is 10Vpp.
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Well, the circuit (Figure 24) is assembled on breadboard. In order to perform experiment please click
on the button "Perform Experiment". If the components have been used those that is not assamble
in the experiments or are connected wrong (e.g. there is a shortcircuit) the error alert will be
provided (¡Error! No se encuentra el origen de la referencia.6).
Figure 26: VISIR – Error alert/message
If the correct components are used and connections have been done well, no message will be
appered and we can go the last step - connecting the oscilloscope and observing the signals.
Press on the Button oscilloscope and Figure 27 will appear.
Figure 27: VISIR – Oscilloscope
In order to see the INPUT signal - Channel 1 on the wiring circuit, we should activate the button”1”
and for OUTPUT - Channel 2 on the circuit, the button “2” on the area 4 (¡Error! No se encuentra el
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origen de la referencia.). After clicking on “Perform Experiment”, the oscilloscope will display the
input and output signals of the created circuit (Figure 24) as shown on the Figure 28.
Figure 28: VISIR – signals from Channel1 and Channel2
NOTE: Please do not click on RUN button - it needs a large bandwidth. In RUN mode, the
oscilloscope is always asking for new data to the server. The buttons “Perform Experiment” on the
interface and “Single” on the oscilloscope interface execute the same action: one image is captured.
5
Q&A: Question and Answer
Q1: I connect to the page and nothing appears.
A1: It may be because you have not installed the Flash module. By default it should be included. If
not, you can download it from http://www.adobe.com/products/flashplayer/
Q2: I put the components in the breadboard and I get an error when press "Perform experiment"
A2: It may be for several reasons: you're using a different component to those corresponding to the
experiment. Please check a circuit. Remember that the holes in columns are interconnected.
Q3: There is no signal on the oscilloscope display. The presentation of the signal is not changed.
A3: Solution: (1) press the button "Perform experiment"; (2) activate the channel of the oscilloscope
(button 1 or button 2)
Q4: I want to measure a voltage with the multimeter (DMM) and I get nothing or what I see is not
consistent.
A4: Check connection of the multimeter in the circuit. After any changes in the circuit press button
"Perform Experiment" again.
Q5. I want to measure current. I get error when connecting DMM
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A5: Check DMM connection: to measure currents use the "breaking the circuit" (check Figure 23 of
this instruction for the information).
Q6: I set the function generator and cannot get 20Vpp and offset of 5V.
A6: The maximum amplitude of the function generator is 10Vpp. The offset is depends on the
amplitude of the signal.
Q7: I want to set a voltage of 12V
A7: Connect the +25V output to the circuit on the breadboard and press the button +25 V on the DC
Power (4.3.2).
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