55:041 Electronic Circuits
The University of Iowa
Fall 2006
A Guide to Using the NI ELVIS System
Contents:
I. .......... Introduction
II. ......... Bench-top Workstation
III......... Common Instrument Functions and
Important Notes on ELVIS
IV......... Digital Multi-Meter
V. ......... Oscilloscope
VI......... Function Generator
VII. ...... Variable Power Supplies
VIII. ..... Bode Analyzer
IX......... Dynamic Signal Analyzer
X. ......... Arbitrary Waveform Generator
XI......... Digital Reader
XII. ...... Digital Writer
XIII. ..... Impedance Analyzer
XIV. ..... Two-Wire Current-Voltage Analyzer
XV........ Three-Wire Current-Voltage Analyzer
1
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
I: Introduction:
The Educational Laboratory Virtual Instrumentation Suite (ELVIS) produced by
National Instruments (NI) is designed to simulate several pieces of electronic laboratory
equipment. It eliminates the need for bulky equipment in the lab. It also allows for the
design of customized instrumentation that can be used for specific projects.
The entire NI ELVIS system is built on top of NI’s Labview software and
hardware, and is comprised three main components as shown and described below:
1.
ELVIS software on the PC, which
provides a graphical interface for several
electronic instruments. These instruments
are discussed in detail throughout the rest of
this guide.
2.
The PC connects to the bench-top
workstation through the data acquisition
board. This board has both analog and
digital input and output lines.
3.
The bench-top workstation provides
electrical connections for the user to
interface with circuits. These provide inputs and outputs for the virtual instrumentation
provided by the ELVIS software. There is a prototyping board (breadboard) on the top of
the workstation with several holes connected through the data acquisition board. There is
also a front interface on the workstation with controls for a few select instruments.
To access the ELVIS software, go to
Start>All Programs>National Instruments>
NI ELVIS 2.0>NI ELVIS
or click on a shortcut:
To the right is the startup screen shown
when NI ELVIS first opens.
The
configure
button
establishes
communication with the workstation.
LabVIEW can also be launched to make
user-defined custom instrumentation (This is
not described in detail in this guide).
All other buttons open different NI ELVIS
instrumentation.
2
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
II. Bench-top Workstation
On top of the workstation is the prototyping board
(referred to in this guide as the breadboard).
On the front of the workstation are several controls and interfaces to the system.
Controls and connections on the bench-top workstation are described below:
3
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
System controls on the front of the workstation:
SYSTEM POWER indicator light – If the system switch on the back side of the
workstation is on, this light will be lit.
PROTOTYPING BOARD POWER indicator light – If the breadboard power
switch to the left is on, this light will be lit. Nothing on the breadboard
will work without this switch turned on.
COMMUNICATIONS switch and light – The communications switch should
be set to normal while the ELVIS software is being used.
The two most widely-used voltage producing instruments have controls on the
front of the workstation. The two most widely-used measuring instruments have
connections on the front of the workstation, which are also connected to the same holes
on the left side of the breadboard. (NOTE: do not use the same connections for these
instruments on the breadboard and on the front of the workstation at the same time)
Breadboard holes:
The bulk of the breadboard is made up of holes that are not connected to the data
acquisition board and the PC. These connections are just like a normal breadboard that
can be found in any circuits laboratory. The connections on the four red and blue +/sections are made in vertical columns. The connections in the three other sections are
made in sets of five horizontal holes separated by the valley in the middle.
Special holes on the breadboard:
These are the holes that are found on the far left and far right of the breadboard.
They consist of several sets of four horizontal holes that are also connected to the PC for
special functions. The different types of holes are described below.
DC Power Supplies – These holes are always on, and produce a constant DC
voltage as long as the breadboard power switch is flipped.
Communication – These holes communicate in one way or another with t he data
acquisition board and the PC. They often have multiple functions, and are
described in more detail throughout the rest of this guide.
User Configurable I/O – These holes connect to the several connecters on the
left and right edges of the circuit board on which the breadboard rests.
NOTE: Grounding – All of the “special holes” that are marked as ground on the
breadboard are connected and equivalent. This does not include black or minus
holes as found on the analog channels, the oscilloscope channels or the voltage
low hole for the DMM. Make sure to ground these when using.
4
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
III. Common Instrument Functions and Important Notes on ELVIS
Common Functions: These are buttons or functions common to two or more instruments
in the ELVIS software package. Their functions are described below.
RUN or RUN / SINGLE buttons – There are three different types of RUN buttons. On
some measurement instruments, there is a RUN button next to a SINGLE button.
If the RUN button is pressed, the measurements are taken continuously. If the
SINGLE button is pressed, a single measurement is taken at that instant.
The Bode and Current-Voltage Analyzers are special because they both
produce signals and make measurements. They have a RUN button that, when
pressed, starts the function of these instruments.
LOG function – On some measuring instruments, the user can save a text file that
records all data of the current display. This text file can be used by another
program to analyze the data. For example, if the text file is opened using
Microsoft Excel, the graph can be recreated, and trend-lines added to it.
MANUAL switch / indicator lights – The Variable Power Supplies and the Function
Generator can be controlled either by their ELVIS software components or the
controls on the front of the workstation. Turn the MANUAL switch on to use the
controls on the front. There is an indicator of this in the software. The software
cannot be used if the switch is on.
CURSORS / MARKERS – Many plotting instruments have cursors or markers that can
be displayed on the plots. They are turned on by buttons and manipulated by
clicking directly on the cursor in the plot display.
IMPORTANT NOTES on the particularities of certain ELVIS instruments:
DC Voltage & Signal producing instruments – These instruments don’t always
produce exactly what the displays say they are producing. They should be
measured and readjusted until the desired signal is produced.
Measuring Instruments – Because these measurements are on digital displays and have
many significant digits, tiny fluctuations may cause changes in the value
displayed. There are often more digits than are necessary, so the fluctuations
represent very tiny movements that aren’t important. When measuring, try to take
the average value.
Using Multiple ELVIS Instruments Simultaneously – Many instruments can be used
at once, so long as they do not have the possibility of using the same connections
on the workstation. If such conflicts may exist between two instruments, the
ELVIS system will display an error message when the second instrument is
opened, and one of the instruments will not function.
IMPORTANT: Read about nulling the DMM to current before measuring it.
5
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
IV. Digital Multi-Meter (DMM)
Purpose:
To Measure AC and DC
voltages and currents, values of resistance,
capacitance and inductance. Also has a
diode test and a continuity test.
Connections: Current Hi/Lo & Voltage
Hi/Lo banana clip terminals on the front of
the workstation or sets of holes on the
lower-left side of the breadboard. Do not
use the banana clips and the holes at the
same time when making measurements.
Operation: Depending on the function, connect the Current Hi/Lo or the Voltage
Hi/Lo connections to a circuit or element in various ways that are described in detail
below.
Controls:
FUNCTION buttons – Toggle through the 9 different functions available. Each
function is described in detail below.
Buttons common to all functions:
NULL button –Each function must be nulled separately before measuring in that
function. This is done to immediately calibrate the instrument to lab and
circuit conditions. Every function, with the exception of current, only
needs to be nulled once and can then measure many different values.
RANGE buttons – On the lower-left of the DMM. Each function will have
different choices for the maximum values of each range. The range can be
user-selected by pressing the buttons below each maximum value, or the
range can be automatically set by the DMM as values change by pressing
the AUTO button on the left.
Operation of each function:
Voltage (AC and DC):
Connection: Voltage Hi/Lo holes or banana clip terminals
Nulling:
Short the high and low connections and press NULL
Measuring: Always measure voltage in parallel between two nodes
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Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
Current (AC and DC):
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
1.
Attach either lead to the circuit where you intend to break it
2.
Make sure the other lead is not connected to anything
3.
Press the NULL button
4.
Break the circuit and measure
NOTE: If you measure in a different place in the circuit, you have
to null the circuit again.
Measuring: Measure current in series with the element (break the circuit)
Resistance:
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
Short the high and low connections and press NULL
Measuring: Attach one lead to each side of the resistor. Never measure
resistance while the resistor is connected to anything else.
Capacitance:
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
Open the high and low connections and press NULL
Measuring: Attach one lead to each side of the capacitor. Never measure
capacitance while the capacitor is connected to anything else.
Inductance:
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
Short the high and low connections and press NULL
Measuring: Attach one lead to each side of the inductor. Never measure
inductance while the inductor is connected to anything else.
Diode Test:
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
Short the high and low connections and press NULL
Measuring: Put the high lead on the anode and the low lead on the cathode
Continuity Test:
Connection: Current Hi/Lo holes or banana clip terminals
Nulling:
Short the high and low connections and press NULL
Measuring: Attach one lead to each end of the wire or circuit to see if there is a
connection
7
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
V. Oscilloscope (Scope)
Purpose: To Measure
voltage waveforms on
two different channels.
Connections: 3 BNC
terminals on the front of
the workstation or 3
sets of +/- holes on the
upper-left side of the
breadboard. The three
sets are Channel A,
Channel B and External
Trigger inputs.
Operation: Connect the black lead or – terminal to ground and the red terminal to the
voltage to be measured. The separate controls for channel A and channel B are identical.
There are also time and trigger controls that apply to both channels.
Channel A / B separate controls:
ON / OFF button – Controls whether this channel is currently displayed
MEAS button – If selected, the frequency, VRMS and Vp-p of the channel will be
displayed
SOURCE pull-down menu – The scope can actually use one of several inputs
from the breadboard. They are selected from this menu.
VERTICAL dial – Moves the display of the waveform measured on either
channel A or B up or down on the screen.
ZERO button – Removes any vertical display offset made using the vertical dial.
SCALE dial and menu – Controls the voltage scale of each channel. The
voltage displayed in the menu box is per each horizontal green line on the
display.
COUPLING menu – DC coupling displays the true signal with any DC offset.
Selecting AC coupling removes this DC offset on the display.
AUTOSCALE button – The scope will automatically select a voltage scale for
this channel.
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Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
Controls that don’t depend on channel:
TIMEBASE dial and menu – Controls the time scale of the display. The time
displayed in the menu box is per each vertical green line on the display.
TRIGGER controls – The trigger controls what part of the waveform is placed at
the left of the display, and keeps the display in one place horizontally (if it
can find what it is set to trigger on). There is a menu for the source of the
trigger, a dial and for the voltage level to trigger on, an analog/digital
selector and a button that tells whether to trigger on the upstroke or the
downstroke of the waveform.
CURSOR controls – The user can place two cursors on the display by toggling
the ON/OFF button. The menus select whether each cursor is on channel
A or B. The cursors can be moved by using the mouse directly on the
display. Also, measurements displayed directly below the scope display
are from the voltage values and difference in time between the two
cursors.
TIMEOUT / ACQUIRED indicators – The timeout indicator will light up if the
signal is temporarily lost.
VI. Function Generator
Purpose:
To
produce
simple
sinusoidal, square and triangle waveform
voltages.
Connections: One single-ended set of
holes on the lower-left side of the
breadboard. It is assumed that the
ground connection found elsewhere is
used.
Operation: The output of the function
generator is between the FUNC_OUT
holes and ground. There are manual
controls on the front of the workstation.
They parallel the software controls, but
have less functionality.
Controls:
ON button – When pressed, the function generator will continuously produce a
signal.
9
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
Frequency controls – The frequency range of the dial is set by the COARSE
adjustment buttons. The exact frequency is set by the FINE dial. The
frequency can also be directly changed using the box below the dial.
Waveform buttons – The button that is depressed determines whether the signal
produced is a sinusoidal, square or triangle wave.
Peak Amplitude knob – Controls the single-sided (not peak-to-peak) amplitude
of the output.
DC Offset knob – Controls the offset voltage of the output waveform.
Frequency Sweep controls – The instrument can automatically sweep through
several frequencies in a short time. The start, stop and step frequencies
can be set. The frequency sweep starts with the play button and ends
when the stop frequency is reached or the stop button is pressed.
VII. Variable Power Supplies
Purpose:
To produce two different DC
voltages; one between -15 and 0 volts, and
another between 0 and +15 volts.
Connections: 3 sets of holes on the lowerleft side of the breadboard. The holes are
Supply+, Supply- and Ground. Also, there
are manual controls on the front of the
workstation.
Operation: The outputs exist between
either ground and Supply+ or ground and Supply- on the breadboard. There are manual
controls that parallel the software controls with the same functionality. The manual
controls can be accessed separately for each supply.
Controls:
Voltage controls – The dials control the voltages of the two voltage supplies
independently. The voltages can also be set by typing the voltages into the
boxes below the dials.
10
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
VIII. Bode Analyzer
Purpose:
To analyze filter circuits to produce both gain vs. frequency and phase vs.
frequency semi-logarithmic bode plots.
Connections: Uses analog channels 0 and 1, two sets of +/- holes located at the top-left
corner of the breadboard.
Operation:
The FUNC_OUT holes must be connected to ACH1 as well as to the input
of the circuit to analyze. The output of the circuit must be connected to
ACH0. This is shown in the simple diagram below.
ACH1+
ACH0+
FUNC_OUT
Input
Filter
Circuit
ACH1-
Output
ACH0-
Controls:
Settings – The function generator output (input to your circuit) can be controlled
using these settings. Controls the frequency sweep start, stop and number
of steps as well as amplitude and whether or not the signal is inverted.
Display – Controls the Y scales of the phase and gain plots separately. Decibels
can be toggled on or off. Also, the user can display a set of cursors on the
plots which can be moved by clicking directly on the display.
11
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
IX. Dynamic Signal Analyzer
Purpose:
To display the input signals in the frequency domain.
Connections: Choose between one of eight sets of +/- analog channels on the top-left
corner of the breadboard.
Operation: Any voltage signal can be connected to an analog channel and analyzed with
this instrument. It will display the signal in the frequency domain, as well as a
smaller display in the time domain.
Controls:
Input Settings – Selects the source of the input as well as the range of voltages of
the input signal.
FFT Settings – This instrument uses a Fast Fourier Transform algorithm to
produce the frequency domain analysis of the input signal. Control the
frequency range and space between frequencies with these settings.
Averaging Settings – This instrument also averages the input signal using
different modes of averaging which can be selected.
Triggering Settings – Control the source, voltage level and type of triggering
used when measuring the input signal.
Frequency Display Settings – Control the units and type of magnitude displayed.
Also, display markers on the plot or change the scale.
12
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
X. Arbitrary Waveform Generator
Purpose:
To produce arbitrary voltage
waveforms as designed by NI’s waveform
editor.
Connections: The two sets of analog output
holes labeled DAC0 and DAC1 on the
lower-left side of the breadboard.
Operation: The two output channels are
between either DAC0 and ground or DAC1
and ground. It is assumed that ground is
found elsewhere. In order to produce a
waveform, the user must first be create a
.wdt file using NI’s Waveform Editor.
There is a shortcut to this program just
below the display.
Controls:
DISPLAY controls – In the lower-right corner of the display window. Zoom in
and out and manipulate the axes of the current display.
OPEN FILE button – Once a .wdt file is created, it can be loaded into either
output channel by first opening it with the OPEN FILE button. The box to
the left shows which file is currently loaded. The CLEAR button empties
the loaded file.
GAIN box – The input waveform is scaled according to the value in this box.
UPDATE RATE box – Adjusts how many points per second are produced.
TRIGGER SOURCE menu – Selects which source to trigger on.
MODE button – Toggles between repeating the output and just running it once.
PLAY/STOP buttons – These buttons start and stop the instrument from actually
outputting the waveforms on the two different channels. They can be
produced at the same time or separately.
13
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
XI. Digital Reader
Purpose:
To read eight digital
inputs with either high or low values.
Connections: The eight holes labeled
DI 0 through DI 7 located on the upperright side of the breadboard. It is
assumed that a ground connection found
elsewhere is used.
Operation: The eight digital inputs correspond to the eight different indicator lights in
the display. The lighter blue (lit) corresponds to a logic-1 value, which is +5V. The
darker blue (unlit) corresponds to a logic-0, which is 0V. The byte measured is also
displayed as hex above these eight indicators. The instrument can take a single
measurement, or be set to read continuously.
XII. Digital Writer
Purpose:
To produce eight digital
outputs as either +5V (hi) or 0V (lo).
Connections: The eight holes labeled
DO 0 through DO 7 located at the topright corner of the breadboard. It is
assumed that a ground connection found
elsewhere is used.
Operations: The eight blue indicators
and numeric value are the same as in the
digital reader. They correspond to the
eight digital outputs.
Controls:
WRITE button – Starts and stops the instrument’s output.
MODE button – Toggles between repeating the output and just running it once.
PATTERN menu – Selects manual or automatic pattern production.
MANUAL PATTERN switches – These eight switches correspond to the eight
outputs in manual pattern selection.
ACTION controls – Pressing each of these three buttons manipulates the current
pattern in three different ways. The direction switch toggles between
moving the pattern to the left or right when ROTATE or SHIFT is pressed.
14
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
XIII. Impedance Analyzer
Purpose:
To analyze the
full impedance (resistance and
reactance) of an element or a
simple circuit.
Connections: Uses either the
Current Hi/Lo holes on the
lower-left
side
of
the
breadboard or the same banana
plugs on the front of the
breadboard.
Operation: Connect one or
more simple elements using the
breadboard, but do not connect
them to ground.
Connect
Current Hi to one side of this
simple circuit, and Current Lo
to the other.
The total
impedance is displayed in both
polar and complex forms:
Z = Magnitude∠Phase = R + jX
Controls:
DISPLAY settings – The VISIBLE SECTION controls cycle through the
quadrants of the plot that are currently visible. The SCALE button toggles
between linear and logarithmic scales.
MEASUREMENT FREQUENCY box – Remember that the reactance is a
combination of the capacitance and/or inductance values and the
frequency of the current/voltage in the circuit. The frequency used to
analyze the current simple circuit can be changed in this box.
RUN button – Toggles between taking a single measurement and measuring
continuously.
15
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
XIV. Two-Wire Current-Voltage Analyzer
Purpose:
To analyze
the
current-voltage
characteristic of a twoterminal
element
or
simple circuit.
Connections: Uses either
the Current Hi/Lo holes
on the lower-left side of
the breadboard or the
same banana plugs on the
front of the breadboard.
Operation: Connect Current Hi to one side of the element or simple circuit, and
Current Lo to the other. The instrument sweeps through several voltages and measures
the current for each.
Controls:
VOLTAGE SWEEP settings – Control the start, stop and step values of the
voltages applied by the instrument.
CURRENT LIMITS settings – Set the cut off limits for measuring current.
There is a maximum amplitude that the instrument can handle and it won’t
let the user set the CURRENT LIMITS higher than this.
RUN button – Starts the instrument’s analysis of the current circuit.
LOG button – Creates a text file with current plot information.
DISPLAY settings – Toggle the auto-scale function of the instrument, and the
linear, semi-log or logarithmic plots available. Also, a cursor can be
displayed and manipulated on the plot.
16
Author: Colbin Erdahl
55:041 Electronic Circuits
The University of Iowa
Fall 2006
XV. Three-Wire Current-Voltage Analyzer
Purpose:
To analyze
the
current-voltage
characteristic of a threeterminal device or simple
circuit.
Connections: Uses
Current Hi, Current
and 3-Wire holes on
lower-left side of
breadboard.
the
Lo
the
the
Operation: Connect the
device as shown in the
lower-left corner. B, C
and E nodes are G, D and
S in MOSFETs.
The instrument sweeps through collector voltages for a number of base currents and
measures the collector current. Each base current lends a different colored curve on the
plot.
Controls:
BASE CURRENT settings – Control the base current applied to the circuit with
start, step and number of currents.
COLLECTOR VOLTAGE settings – Control the collector voltage sweeps with
start, stop and step values. Also controls the limit to the output collector
current. There is a maximum current allowed by the instrument.
RUN button – Starts the instrument’s analysis of the current circuit.
LOG button – Creates a text file with current plot information.
DISPLAY settings – Toggle the auto-scale function of the instrument, and the
linear, semi-log or logarithmic plots available. Also, a cursor can be
displayed and manipulated on the plot.
17
Author: Colbin Erdahl