Quanser QNET User manual

USER MANUAL
QNET Myoelectric Trainer for NI ELVIS
Set Up and Configuration
CAPTIVATE. MOTIVATE. GRADUATE.
Solutions for teaching and research. Made in Canada.
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QNET MYOELECTRIC- User Manual 2

Contents
1 Introduction 4
2 System Description 5
2.1 MYOELECTRIC Components 5
3 System Schematic 7
4 Specifications 8
5 Environmental 9
6 Setup Guide 10
6.1 QNET and NI ELVIS II Setup 11
7 QNET LabVIEW Hints 14
7.1 Scaling Scopes 14
7.2 Saving Response 15
8 Troubleshooting 18
8.1 General Software Issues 18
8.2 General Hardware Issues 18
9 Technical Support 20
QNET MYOELECTRIC- User Manual v 1.0

1 INTRODUCTION
The Myoelectric Trainer (MYOELECTRIC) is designed to teach and demonstrate the fundamentals of processing
electromyographic signals. The system can be configured to utalize a veriety of filtering and control methods to
process the muscular signals and control the position of the clamps on the servo. In particular, the system can be
used to teach linear envelope filtering, zero-order hold, position control and the basics of LabVIEW coding. This is
done using a PC with real-time control capabilities and the NI ELVIS II. The hardware of the MYOELECTRIC trainer
is described in Section 2. A schematic of the hardware components is included in Section 3, and the specifications
are listed in Section 4 and Section 5. Some helpful LabVIEW hints when using the QNET VIs are given in Section
7 along with a troubleshooting guide in Section 8.
Figure 1.1: QNET Myoelectric Trainer (MYOELECTRIC)
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2 SYSTEM DESCRIPTION
2.1 MYOELECTRIC COMPONENTS
The components comprising the Myoelectric Trainer are labeled in Figure 2.2, and are described in Table 1.
Caution: Ensure the trainer is setup as dictated in the QNET Setup Guide. The trainer is susceptible to protection
impairment if not used as specified.
ID# Description ID# Description
1 Ground Strap Connector 9 +15V, -15V, +5V LEDs
2 EMG Sensor Connector 10 Servo Motor Connector
3 EMG Power On/Off SW2 Switch 11 Servo Motor
4 Battery Power Supply for EMG 12 Servo Clamps
5 PCI connector to NI ELVIS: for interfacing QNET module with DAC 13 15V QNET power jack
6 AD1 Jumper 14 EMG sensor strap
7 AD2 Jumper 15 Grounding strap
8 AD5 Jumper 16 Fuse
Table 1: Myoelectric component nomenclature
Figure 2.2: General layout of QNET MYOELECTRIC
2.1.1 Servo Motor
The servo motor supplied with the QNET Myoelectric trainer is controlled by a PWM signal and has an operating
range of 4.8-6.0 V, as given in Table 2.
QNET MYOELECTRIC- User Manual v 1.0

2.1.2 Isolation Amplifier
The HCPL-7800 optical isolation amplifier is used to amplify the electromyogram signal measured by the EMG
electrode, remove noise, and isolate the power source from the user. See the Opto Isolation block in Figure 3.4.
The amplifier has a gain of 8.0 V/V and its output voltage ranges between 1.29 V and 3.8 V. The output of the
isolation amplifier can be measured on A/D #1 when the DIP switch is set to OPTO_OUT.
2.1.3 Muscle Contraction Measurement: EMG Sensor
The EMG Sensor consists of a two-electrode eletromyograph and a grounding strap with a ground electrode. It has
an on-board gain of 300 V/V and a local band-pass filter with lower and upper cutoff frequencies of 25 Hz and 500
Hz, respectively. The electromyogram signal measured by the electromyograph relative to the ground terminal that
is amplified by the isolation amplifier can be measured be measured on D/A #1 by setting the AD1 DIP switch to
OPTO_OUT. The amplitude of the raw EMG signal is small and the signal is offset at around 2.5 V. As shown in
Figure 3.4, the signal is then amplified to fit the ±10 V range and biased to 0 V. This processed signal is available
on A/D #0 and is used to measure the amount of muscle contraction.
Caution: Make sure that the two 1.5 V AA batteries that power the EMG sensor are inserted correctly.
2.1.4 DIP Switches
The AD1, AD2, and AD5 DIP Switches dictate what signals can be measured on the Digital-to-Analog lines 1, 2,
and 5, respectively. The AD1 DIP switch, components #6 shown in Figure 3.3, is used to measure the 555 timer or
the output of the optical isolation circuit on D/A #1. As shown in Figure 3.4, the OPTO_OUT is the electromyogram
signal that is measured by the EMG sensor and amplifier and offset by the isolation amplifier. It is offset by about
2.5 V. The 555 Timer resembles a sawtooth wave, but is more like an integrated pulse signal.
Use the AD2 DIP switch, ID #7 in Figure 2.2, to view either DA0_AMP or PRE_STAGE_OFFSET on D/A #2. The
DA0_AMP signal is the processed Digital-to-Analog #0 channel output, as illustrated in Figure 3.4. This is the A/D
#0 signal, i.e. the analog output signal supplied to DAQ, that is scaled down and offset by the post stage offset value
before getting passed to the comparator. The PRE_STAGE_OFFSET is a constant value. It is the offset used to
bring the EMG signal to be around 0 V.
The AD5 DIP switch, component #8 shown in Figure 2.2, determines what signal can be viewed on D/A #5 -
PWM_SIG or POST_STAGE_OFFSET. The PWM_SIG is the pulse-width modulated signal being sent to the servo.
It is the result of passing the 555 Timer pulse and the processed A/D#0 signal through a comparator. The
POST_STAGE_OFFSET is the offset used to regulated the attenuated A/D#0 signal to be about 0 V.
2.1.5 555 Timer
The National Semiconductor LM555CM-ND is a high-precision 555 timer integrated circuit that is used for the PWM
cycles. It can be monitored on A/D#1 by setting AD1 DIP switch to 555_REF.
2.1.6 QNET Power Supply
The DCMCT module has a 15-Volt DC power jack to power the on-board ICs. It is called the QNET Myoelectric
power supply.
Caution: Please make sure you use the correct type of wall transformer or you will damage the system. It should
supply 15 VDC and be rated at 5.0 A. The QNET Myolectric does NOT use the same power supply as other QNET
systems.
Note: The fuse is replaceable and is rated at 2A 250VAC, type slow-blow, size 5x20 mm.
QNET MYOELECTRIC- User Manual 6

3 SYSTEM SCHEMATIC
A schematic of the MYOELECTRIC system interfaced with a DAQ device is provided in Figure 3.3. The block
diagram representing the circuit in the Myoelectric board is shown in Figure 3.4.
Figure 3.3: Schematic of QNET Myoelectric trainer
Figure 3.4: QNET Myolectric circuit block diagram
QNET MYOELECTRIC- User Manual v 1.0

4 SPECIFICATIONS
The specifications of the MYOELECTRIC trainer are given in Table 2.
Symbol Description Value Unit
Servo Motor:
Operating Range 4.8-6.0 V
MHStall torque 3 kg·cm
Diemsions 29 x 13 x 30 mm3
msWeight 0.02 kg
EMG Sensor:
Analog output range ±5 V
Gain 300 V/V
Upper cut-off frequency 500 Hz
Lower cut-off frequency 25 Hz
Common mode rejection ratio 80 dB
Supply voltage (typical) 5.00 V
Isolation Amplifier:
VM AX Recommended input voltage (accurate and linear) ±0.200 V
|VIN |M AX Maximum differential input voltage 0.308 V
GGain 8 V/V
VOL Output low voltage 1.29 V
VOH Output high voltage 3.8 V
Bandwidth 100 kHz
Supply Voltage 5.5 V
Table 2: MYOELECTRIC specifications
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5 ENVIRONMENTAL
The Myoelectric Trainer environmental operating conditions are given in Table 3.
Description Value Unit
Operating temperature 15 to 35 ◦C
Humidity 20 to 90 %
Table 3: MYOELECTRIC environmental operating conditions
Caution: Ensure the unit is operated under the temperature and humidity conditions given in Table 3. Otherwise,
there may be some issues with the heating and cooling results.
QNET MYOELECTRIC- User Manual v 1.0

6 SETUP GUIDE
As illustrated in Figure 6.5, the QNET boards can easily be connected to an NI ELVIS system. The instructions in
Section 6.1 detail the setup procedure for using a QNET with an NI ELVIS II.
Figure 6.5: Connecting a QNET Trainer
Caution: Do not position the ELVIS II so that it is difficult to disconnect the main power.
Caution: If the equipment is used in a manner not specified by the manufacturer, the protection provided
by the equipment may be impaired.
QNET MYOELECTRIC- User Manual 10

6.1 QNET AND NI ELVIS II SETUP
The procedure to install a Quanser Engineering Trainer (QNET) module on the NI ELVIS II is detailed in this section.
The NI ELVIS II components used in the installation procedure are located and marked by an ID number in Figure
6.6, and described in Table 4.
6.1.1 ELVIS II Components
Figure 6.6: Components on ELVIS II
ID# Description
1 NI ELVIS II
2 Prototyping board power switch
3 Power LED
4 Ready LED
5 Power Cable for ELVIS II
6 USB Connection between PC and ELVIS II
Table 4: ELVIS II components
QNET MYOELECTRIC- User Manual v 1.0

6.1.2 ELVIS II Setup Procedure
Follow these instructions to setup a QNET board on an ELVIS II:
Caution: Do NOT make the following connections while power is supplied to the hardware!
Caution: The unit is provided with a grounded cord to be used with a properly grounded outlet only, this
is a safety feature, do not disable it
1. Place the small opening on the front of the QNET board over the mounting bracket on the NI ELVIS II.
2. Slide the PCI connector of the QNET module end into the female connector on the NI ELVIS II. Make sure it is
connected properly.
3. Connect the ELVIS II power cable.
4. Connect the ELVIS II USB cable to the PC.
5. Connect the supplied QNET transformer to the QNET power jack on the QNET module.
6. Connect the myoelectric sensor and grounding straps.
7. Power the NI ELVIS II by turning ON the System Power Switch on the rear panel.
8. Turn ON the Prototyping Board Power switch, ID #2 shown in Figure 6.6.
Caution: Take extra care when powering the QNET module to avoid causing any damage!
9. The Power and Ready LEDs of the NI ELVIS II unit should be lit as shown in Figure 6.7.
Figure 6.7: Ready and Power LEDs on NI ELVIS II
10. As pictured in Figure 6.8, verify that the +15V,-15V, and +5V LEDs on the QNET module are lit. They indicate
that the board has been properly connected to the ELVIS unit.
QNET MYOELECTRIC- User Manual 12

Figure 6.8: QNET LEDs should all be ON
11. Power ON the myoelectric sensor power.
12. Ensure that the Battery ON LED is lit, as shown in Figure 6.9.
Figure 6.9: Battery LED should be ON
QNET MYOELECTRIC- User Manual v 1.0

7 QNET LABVIEW HINTS
7.1 SCALING SCOPES
This section describes a handy method of changing the x or y axis in a LabVIEW scope using
QNET_DCMCT_Swing_Up_Control VI as an example. Read the steps below to reduce the y-axis range of the
Angle (deg) scope shown in Figure 7.10 in order to see the blue trace more up close.
Figure 7.10: Scope needs to be scaled
1. As illustrated in Figure 7.11, to decrease the positive range of the scope down to 40, double-click on '100' in
the y-axis, type in '40', and press ENTER.
Figure 7.11: Scope needs to be scaled
QNET MYOELECTRIC- User Manual 14

2. The resulting scope is depicted in Figure 7.12. The blue trace is now more visible.
Figure 7.12: Y-axis of scope has been adjusted
Similarly, the minimum range of the y-axis can be changed as well as the range of the x-axis. For example, to see
a time range of 10 seconds instead of 5 seconds the x-axis range can be changed from [0.0, 5.0] to [0.0, 10.0].
However, when changing the x -axis, i.e. the time-scale, it is recommended to do the following:
1. Pause the scopes or stop the VI and clear the chart (right-click on scope, select Data Operation ∥Clear Chart).
2. Apply the same scale change to both the output and input scopes. Otherwise, the data plotted in each scope
will not be synchronized with each other.
7.2 SAVING RESPONSE
Read the following to save a scope response:
1. Right-click on the scope and select Export Simplified Image, as shown in Figure 7.13
QNET MYOELECTRIC- User Manual v 1.0

Figure 7.13: Right-click on scope and select Export Simplified Image
2. The dialog box shown in Figure 7.14 opens and gives various image export options. One way is to export the
image to the clipboard as a bitmap. This can then be pasted in a graphical software (e.g MS Paint, Irfanview)
and saved to a desired format (e.g. gif).
Figure 7.14: Export Simplified Image dialog box
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3. The resulting image that is saved is shown in Figure 7.15.
Figure 7.15: Sample saved response
The scope can be saved whether or not the VI is running. However, typically it is easier to stop the VI when the
desired response is collected and then export the image as instructed above.
QNET MYOELECTRIC- User Manual v 1.0

8 TROUBLESHOOTING
8.1 GENERAL SOFTWARE ISSUES
Q1 When I try to open a QNET VI, it says there are some missing VIs and they have a ''CD'' or ''Sim'' in the
name?
The LabVIEW Control Design and Simulation Toolkit is not installed.
Q2 When I open a QNET VI a message prompts that a VI with ''ELVIS'' in the name cannot be found?
• ELVIS I: The QNET VIs use drivers that are installed from the ELVIS 3.0 or later CD. Make sure it
is installed. If the folder ''\National Instruments\NI ELVIS 3.0'' does not exist then it is not installed
(available for download at www.ni.com as well).
• ELVIS II: The QNET VIs use the ELVISmx drivers. Make sure you install the contents of the ELVIS II
CD before attempting to open any of the QNET VIs (available for download at www.ni.com as well).
8.2 GENERAL HARDWARE ISSUES
Q1 None of the LEDs on the QNET board are lit?
Make sure both the System Power switch, which is located on the back of the ELVIS I and II units, and the
Prototyping Board Power switch, which is situated on the front panel of the ELVIS I and on the top-right
corner of the ELVIS II, are ON. See the QNET Setup Guide for more information.
Q2 On the QNET board, the +15V, -15V, and +5V LEDs are bright green but the +B LED is not lit?
Ensure the QNET power connector on the QNET board is connected with the supplied QNET power
cable. See the QNET Setup Guide for more information.
Q3 At least one of the +B, +15V, -15V, and +5V LEDs on the QNET board is not lit?
See Q2 if only the +B is not lit.
If one or more of the +15V, -15V, and +5V LEDs is not lit then a +/-15V or +5V fuse(s) on the Protection
Board of the NI-ELVIS I is burnt. Similarly, if the +B LED is still not lit after connecting the QNET power
then the Variable Power Supplies Fuses on the ELVIS Protection Board are burnt. See the Protection
Board Fuses in the NI ELVIS User Manual and replace the fuses as directed.
Q4 The Ready LED on the ELVIS II does not go on?
QNET MYOELECTRIC- User Manual 18

1. Go through the ELVIS II setup procedure outlined in the QNET Setup Guide
2. Once completed, launch the Measurement & Automation Explorer software.
3. As illustrated in Figure 8.16, expand the Devices and Interfaces and NI-DAQmx Devices items and
select the NI ELVIS II device.
4. As shown in Figure 8.16, click on the Reset Device button.
5. Once successfully reset, click on the Self-Test button.
6. If the test passed, reset the ELVIS II (i.e. shut off the Prototyping Board switch and System Power
switch and turn them back on again). The Ready LED on the ELVIS II should now be lit.
Figure 8.16: Reseting and performing the self-test on the ELVIS II
QNET MYOELECTRIC- User Manual v 1.0

9 TECHNICAL SUPPORT
To obtain support from Quanser, go to http://www.quanser.com/ and click on the Tech Support link. Fill in the form
with all the requested software and hardware information as well as a description of the problem encountered. Also,
make sure your e-mail address and telephone number are included. Submit the form and a technical support person
will contact you.
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