User Manual and Technical Specifications

Electromyography (EMG) Reflex Instrumentation

BIOE 385 - Bioinstrumentation Laboratory Patricia Thai & Karen Vasquez

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Table of Contents

Introduction ……………………………….……………………………………………………...3 Description of Product ……………….…………………………………………………… 3 Physiological Relevance ……………….…………………………………………………. 3 Uses and Features ……………….………………………………………………………... 3

Instructions ……………………………….……………………………………………………... 5 Materials ……………….…………………………………………………………………. 5 Hardware Setup ……………….……………………………………………………....…...6 Electrode Positioning ……………….……………………………………………………..8 Test Procedure …………….……………………………………………………...…….... 10 Tips and Tricks …………………………………………………………………….…..... 13 Safety ……………….………………………………………………………………........ 13

Technical Specifications ………….……………………………………………………..…….. 14 Overview …………….……………………………………………………………………….14 1. Reflex Hammer …………….……………………………………………………………...14

DB9 Connector ………….………………………………………………………………. 14 Reflex Hammer ………….……………………………………………………………….17 Reflex Hammer Measurement & Amplification Circuit ………………………………... 17

2. EMG Signal Measurement ……….………………………………………………………..18 Electrical Isolation (Safety Circuits) ……………………………………………………..18 1st Stage Amplifier …………………………………………………..………………….. 19 Filter Circuit …………….………………………………………………………………. 21 2nd Stage Amplifier …………………………………………………………………….. 22

LabVIEW Program …………….……………………………………………………………. 23 Data Acquisition from Hardware ……….………………………………………………..23 Hammer Signal …………….……………………………………………………………. 24 EMG Signal …………….……………………………………………………………….. 26 Reflex Time …………….……………………………………………………………….. 28 Saving Data to Excel File ………...………...………...………...………...……………... 28 Additional Features for Ease of Use ………...………...………...………...…………….. 30

Challenges & Limitations ………...………...………...………...………...………...…………..32

Appendices …………………………………………………...………...………...……………...33

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Introduction Description of Product The EMG reflex device is able to measure and display the electrical activity caused by the contraction of muscles. The device is used by simply placing electrodes on the muscle of interest. These electrodes are connected to the device, and the measured difference in potential at each electrode is amplified as the EMG signal. The product uses NI ELVIS technology paired with electrode technology. The system will be developed to use a LabVIEW interface to display the reflex hammer and EMG signal as well as the measured reflex time.

Physiological Relevance EMG tests are often used in the medical field to detect problems with the nervous system. The nervous system controls the muscles using electrical signals called impulses. An 1

electromyography (EMG) measures electrical activity generated during muscle stimulus. The electrical signal acquired using EMG depends on the nervous system and therefore also depends on the anatomy and physiology of the muscles. During muscle contraction, an action potential is created along the muscle fibers. The surface electrodes are placed in the direction of the muscle fibers to measure electrical activity at two sites along the action potential. Finally, the difference in the measured potential at both electrodes is amplified, giving the resulting EMG signal. 2

The knee reflex is an example of a spinal reflex activated by tapping the patellar tendon. This test is often used to test for cerebellar disease. The patellar tendon is associated with damage to 3

the L4 and L5 nerves. The patellar reflex is an essential diagnostic tool for such neuromuscular disorders. 4

Uses and Features The EMG device is useful in various medical applications. The EMG device is able to provide insight on nerve conduction. Specifically, this device can be used to determine how fast nerves send signals. This information can then be used to diagnose several diseases involving damaged tissue or nerves.

1 “Electromyogram (EMG) and Nerve Conduction Studies.” Michigan Medicine Gateway, University of Michigan, 2011, www.uofmhealth.org/node/659367. 2 Raez, M.B.I., M.S. Hussain, and F. Mohd-Yasin. “Techniques of EMG Signal Analysis: Detection, Processing, Classification and Applications.” Biological Procedures Online 8 (2006): 11–35. PMC. Web. 9 Nov. 2017. 3 “Cerebellar Exam.” Cerebellar Exam | Stanford Medicine 25 | Stanford Medicine, Stanford University , stanfordmedicine25.stanford.edu/the25/cerebellar.html. 4 Ginanneschi, F, et al. “Pathophysiology of Knee Jerk Reflex Abnormalities in L5 Root Injury.” Functional Neurology, vol. 30, no. 3, July 2015, pp. 187–191., doi:10.11138/fneur/2015.30.3.187.

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Furthermore, the device is very safe and simple to use. The device has a safety circuit integrated into it to eliminate the risk of electrical shock. The electrodes used are also non-invasive pads rather than invasive intramuscular electrode needles.

Professional training is not necessary for the use of this device. The graphical user interface (GUI) includes easy access to the user manual and also gives feedback and help messages to guide the user. Measurement values are automatically displayed and the device automatically informs the user whether or not their reflex time was within an average range. This feature is helpful as an indicator of potential issues. This device also includes a feature that calibrates the EMG signal measurement to the individual in order to minimize error due to variability between users. After measurement, the user can then input patient information and the time/date for each set of data. This data can then be saved and exported as an Excel file for later use or data analysis.

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Instructions Materials

1. NI ELVIS II Series Prototyping Board (Figure 1a) 2. Reflex Hammer (Figure 1b) 3. Medical Tape (Figure 1c) 4. Electrode Gel (Figure 1d) 5. Electrodes (Figure 1e) 6. Banana Plug to Alligator Clip Cable (1 black, 2 red) (Figure 1f,g)

Figure 1: EMG Reflex Device Materials

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Hardware Setup 1. Plug in the power cord and turn on the power switch that is located on the back left of the

NI ELVIS II (Figure 2).

Figure 2: Power Switch (Left) and Power Cord (Right) Located at the Back Left of the NI

ELVIS II

2. Plug in the protoboard by pushing the board up and into the corresponding plug at the top of the NI ELVIS II (Figure 3).

Figure 3: NI ELVIS II Before Plugging in the Protoboard (Left) and After Plugging in the

Protoboard (Right)

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3. Plug in the reflex hammer to the DB9 connector on the protoboard (Figure 4).

Figure 4: Connecting the Reflex Hammer

4. Connect three alligator to banana plug cables to the protoboard (Figure 5). The banana plug connections are located on the left side of the protoboard. Connect the black cable into banana B. Connect the red cables into banana A and banana C.

Figure 5: Connecting Banana Cables to Protoboard

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5. Turn on the “Prototyping Board” power switch located at the top right of the NI ELVIS II. The power light should be green when you flip the switch (Figure 6)

Figure 6: Power Switch for the Prototyping Board of the NI ELVIS II

6. Open LabVIEW interface

Electrode Positioning 1. Dab a small amount of gel onto the electrodes. Be careful not to put too much gel. The

gel should only cover the green part of the electrode (Figure 7).

Figure 7: Electrode Gel

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2. Place an electrode on the center of the knee cap (Figure 8a ). 3. Determine the location of electrode placement by having the subject extend their leg.

Doing so will allow them to see their quadriceps. (Figure 8a). 4. Place an electrode on the start of the quad muscle (Figure 8b). 5. Place an electrode four inches above the start of the quad muscle in line with the previous

electrode. (Figure 8b). 6. Clip the black (ground) cable to the electrode on the knee cap (Figure 8b). 7. Clip a red cable to each of the two electrodes on the quad. The red cable connected to

banana A should clip onto the electrode closest to the knee. The red cable connected to banana C should clip to the electrode closer to the hip (Figure 8b).

Figure 8: Placing Electrodes

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Test Procedure 1. After setting up the hardware and positioning the electrodes, open the LabVIEW EMG

reflex GUI (Figure 9).

Figure 9: LabVIEW EMG Reflex GUI

2. Have the subject sit upright with their legs hanging slightly above the floor. 3. Before beginning the test, use the hammer to tap the subject's knee several times until

you find the best spot for a knee jerk (Figure 10).

Figure 10 : Knee Reflex

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4. Mark this spot with a marker or with tape (Figure 11).

Figure 11 : Marking the Patellar Tendon

5. Start the reflex device by clicking Run on the upper left hand side of the GUI. (Figure 12).

Figure 12 : Run Button

6. Calibrate the device by having the patient extend/flex their leg and then clicking the calibrate button. This sets the EMG threshold value. The threshold value can also be input manually if desired. To do this, type in a value then click the reset button. (Figure 13).

Figure 13: Calibration

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7. Input patient information as well as date/time if desired (Figure 14).

Figure 14: Patient Information and Date/Time Input

8. Begin the test by firmly tapping the subjects knee (at the spot marked earlier) and observing the resulting reflex time in the measurements window (Figure 15). You can also view the waveform in the waveform window (Figure 16).

Figure 15: EMG Data Measurements

Figure 16: Signal Waveforms

9. Allow the leg to come to rest before trying again. Repeat test as many times as necessary.

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10. Export the data as an Excel file (Figure 17). Specific measurements can be removed, and all of the measured values can also be reset if needed.

Figure 17: Resetting, Removing, and Exporting Data

Tips and Tricks Be gentle with the hammer when not conducting the test. Dropping or hard placement of

the hammer may be recorded as a signal. The patient should stay relaxed and not move their leg excessively. Keep wires away to prevent noise from movement. Do not hit the knee repeatedly. Wait until the leg has completely stopped moving to start

another reflex test. Have patient clasp their hands to ensure that no extra muscle movements occur.

Safety This device has been created to minimize the risk of electrical shock. Do not use this device around water or food. Do not place device in water and do not use device if water damage is suspected. Keep the electrode gel away from the device and only place it on the electrodes. Do not eat the electrode gel. Do not place any of the connections in your mouth. Do not reuse electrodes to minimize spread of communicable diseases. Carefully arrange cables to avoid entanglement or strangulation. Keep device away from small children.

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Technical Specifications Overview The EMG reflex hardware includes two main components: 1) the reflex hammer and 2) the EMG signal measurement (Figure 18).

The reflex hammer component consists of a reflex hammer connected to the device via a DB9 connector. The hammer signal is then amplified to an appropriate value for measurement and sent to LabVIEW for signal analysis.

The EMG signal measurement component includes electrical isolation safety circuits, amplification circuits, and a filtering circuit. The 1st stage amplifier circuit amplifies the signal enough to be filtered without losing the majority of the signal. The 2nd stage amplifier circuit then amplifies the filtered signal to an appropriate value for measurement and analysis in LabVIEW.

Figure 18: Flow Chart Illustrating the Hardware for the Reflex Hammer and EMG Signal

Measurements

1. Reflex Hammer DB9 Connector The reflex hammer is connected to our device via a DB9 connector. The connector has a total of nine pins, and each of the pins is soldered to its corresponding colored wire as described in Table 1 and shown in Figures 19 and 20.

The positive and negative voltage from the hammer is connected to pins 2 and 3 respectively. The hammer is grounded via pin 3 and is powered via pins 6 and 9 with a +5V and a -5V power supply. The +5 V power supply is from the protoboard itself while the -5V power supply was created by using a voltage divider to convert the -15V power supply to -5V (Figure 21). This voltage divider circuit is composed of 20 kΩ (R 1 ) and 10 kΩ (R 2 ) resistors. The resistor values were chosen according to equation 1 where V in was -15 V and the desired V out was -5 V.

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VV out = in · R2R + R1 2

Equation 1

The shield pins are not currently being used. Although, shielding decreases electrical noise, we have included filters that attenuate this noise from our signal.

Table 1: DB9 Connector Pin-Out Description & Corresponding Wire Color for Hammer

PIN DESCRIPTION WIRE COLOR

1 Shield Green

2 V in + Blue

3 Ground Purple

4 V in - Gray

5 Shield Black

6 + 5 V (ref) Yellow

7 No connection Orange

8 No connection Red

9 - 5 V (ref) Brown

Figure 19: Color-Coded Wires Soldered to their Corresponding Pins Located on the DB9

Connector

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Figure 20: DB9 Male Connector Pin-Out Labels & Descriptions

Figure 21: Voltage Divider Circuit

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Reflex Hammer This device uses reflex hammer 8 (Figure 22). Although other hammers can also be used, this device is optimized for hammer 8.

Figure 22: Reflex Hammer #8

Reflex Hammer Measurement & Amplification Circuit The reflex hammer circuit is an inverting differential amplifier which utilizes an OP07 operational amplifier (Figure 23). The op amp itself is powered with +15V and -15V power supplies and is grounded at the +V in input. The hammer’s signal from pins 2 and 3 enter the -V in and +V in inputs of the op amp respectively (Figure 24). The circuit contains resistors with values 5

of 18 kΩ (R f ) and 1 kΩ (R 1 ) in order to obtain a gain of -18 (Equation 2). This gain was chosen because it amplifies the signal to measurable values. The amplified hammer signal (V out ) is connected to channel ai0 and is observed using an oscilloscope. In the future, this signal will be viewable and used in the LabVIEW VI and user interface.

ain G = −RfR1

Equation 2

5 Although the hammer signal from pin 3 enters the +V in input of the op amp, the reflex hammer signal is from pin 2 (this was discovered by testing whether or not there was signal from each pin). Therefore, we grounded +V in where pin 3 is connected to so that it can act as a reference for the pin 2 signal,.

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Figure 23: Reflex Hammer Measurement & Amplification Circuit Using an Inverting

Differential Amplifier with an OP07

Figure 24: OP07 Operational Amplifier Pin Configuration

2. EMG Signal Measurement Electrical Isolation (Safety Circuits) The purpose of the electrical isolation safety circuit is to protect the user from macroshock in case of circuitry malfunction. It does so by providing a low resistance route to ground when the voltage is greater than 0.6V so that the current flows to ground rather than through the user.

This device has two safety circuits, one for each of the electrodes used to measure the EMG signal on the leg. Each electrode is connected to the device via a red banana cable and is then connected to a 10kΩ resistor and two 1N4148 silicon switching signal diodes in the reverse-biased configuration shown in Figure 25. The reverse-biased configuration prevents

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current from flowing through the diode at voltages below the threshold which is 0.6V. If the voltage is above 0.6V, the diodes will breakdown causing the current to flow through the diode and to ground instead of through to the user. Otherwise, the current from each electrode will 6

flow through to its corresponding V in input of the AD620 (which is described in the next section).

Figure 25: Electrical Isolation Safety Circuit Composed of a 10kΩ Resistor and Two 1N4148

Silicon Switching Signal Diodes

Currents over 10mA causes involuntary muscle contractions and over 18 mA induces respiratory paralysis. Since the 0.6V threshold voltage only allows current below 60µA to flow through the circuit, this device ensures that the user is only exposed to a safe range of currents. , 7 8

1st Stage Amplifier The 1st stage amplifier circuit amplifies the signals from the electrodes using an AD620 instrumentation amplifier (Figures 26 and 27). This instrumentation amplifier was chosen because it allows us to amplify our signal simply by replacing the gain resistor (R G ). Additionally, the AD620 amplifies the signal with less noise than the OP07 and is thus used in the 1st stage of amplification in order to better retain the original signal and minimize noise. The specific R G resistor value that we used was 1000 Ω in order to have a gain of 50. This gain was calculated using Equation 3 and was chosen to amplify the signal just enough to be measured. The signal was not amplified any higher in order to minimize the noise amplification.

ain G = RG49.4 kΩ + 1 Equation 3

The signal from the safety circuit of electrode A (connected to the red banana A input) goes into -V in of the AD620 while the signal from the safety circuit of electrode C (connected to the red

6 Scherz, Paul. Practical electronics for inventors . McGraw-Hill, Inc., 2006. 7 Fish, Raymond M., and Leslie A. Geddes. "Conduction of electrical current to and through the human body: A review." Eplasty 9 (2009). 8 Webster, John. Medical instrumentation: application and design . John Wiley & Sons, 2009.

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banana C input) goes into +V in . The AD620 is powered by +15V and -15V, and V ref is grounded. The output voltage is then connected to channel ai1 for visualization as well as to the bandpass filter circuit described in the next section.

Figure 26: 1st Stage Amplifier Using an AD620 Instrumentation Amplifier with a Gain of 50

Figure 27: AD620 Instrumentation Amplifier Connection Diagram

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Filter Circuit The amplified EMG signal is filtered to remove noise and artifacts. Several types of noise include thermal noise from the circuit components, electrochemical noise from the skin-electrode interface, and movement artifact noise (movement of the electrode on the skin as a result of muscle movement). In order to minimize this noise while still retaining the original signal, measurement within a frequency range of 20 Hz and 450 Hz is recommended. Consequently, the amplified EMG 9

signal is filtered with a second order passive bandpass filter (Figure 28). This filter order was chosen to in order to better attenuate the undesired frequencies. The filter components include two 0.1 µF capacitors (C) as well as 3.6 kΩ (R1), 68 kΩ (R2), and 11 kΩ (R3) resistors cascaded with another set of the same components. The resulting cutoff frequencies are 20.9 Hz ( ) andf c1 442 Hz ( ) (Equations 4 and 5). This bandpass filter’s frequency response is described by thef c2 Bode plot shown in Figure 29. This plot demonstrates that the frequencies below 20.9 Hz and above 442 Hz are attenuated so that the gain is approximately -3 dB at 20.9 Hz and 442 Hz.

0.9 Hzf c1 = 12π(R +R )2 3

= 2 Equation 4

42 Hzf c2 = 12πR1

= 4 Equation 5

Figure 28: Second Order Passive Bandpass Filter with Cutoff Frequencies of 20.9 Hz and 442

Hz

9 De Luca, Carlo J., et al. "Filtering the surface EMG signal: Movement artifact and baseline noise contamination." Journal of biomechanics 43.8 (2010): 1573-1579.

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Figure 29: Bode Plot Showing the Gain and the Phase as a Function of Frequency of the Passive

Bandpass Filter

2nd Stage Amplifier The 2nd stage amplifier circuit amplifies the filtered signal using an inverting OP07 operational amplifier (Figure 30). This additional circuit ensures that the signal is amplified enough to be able to be observed and measured using LabVIEW. The resistor values used for this circuit are 1 kΩ (R 1 ) and 820 kΩ (R f ) resulting in a gain of -820 (Equation 2 in “Reflex Hammer Measurement & Amplification Circuit” section). The amplified signal is then sent through to 10

channel ai2 and will, in future improvements of the device, undergo signal analysis in LabVIEW in order to obtain reflex time.

10 This amplification gain is much higher than the first stage amplification because it does not have to minimize noise amplification, since the noise has already been filtered.

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Figure 30: 2nd Stage Amplification Circuit Using an Inverting OP07 Operational Amplifier

LabVIEW Program In order to calculate the patient’s reflex time, the device uses a LabVIEW code. The following describes the basic path of the hammer and EMG signals from input to output. Figure 31 below shows a simplified flow chart of the LabVIEW signal processing.

Figure 31: Flow Chart Illustrating the LabVIEW Signal Processing

Data Acquisition from Hardware 1. First, the device acquires the hammer signal and the amplified EMG signal using a DAQ

Assistant and uses the Split Signals Function to split the respective signals (Figure 32).

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Figure 32: Data Acquisition and Splitting of Hammer and EMG Signal from Hardware

Hammer Signal 2. The hammer signal is then converted from dynamic data to a waveform in order to be

read by the peak detector function. 3. The hammer signal has an inherent noise even when it isn’t being used (striked). We only

want to record data values for the hammer when the hammer is active (striking something). Therefore, the hammer signal is put through the Peak Detection VI in order to only record data above a peak threshold. This threshold is set to be right above the resting noise amplitude of the hammer (Figure 33).

Figure 33: Detection of Hammer Hit (Peak) Signal Using the Peak Detection VI and the Get

Waveform Components Function

4. Whenever a hammer signal above the threshold is detected, the time of that signal is then found. The time at which the recorded hammer signal occurred is acquired using information on the number of iterations already passed and the sampling frequency. First

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the time of the hammer signal within the current loop iteration is found. This is done by multiplying the location of the recorded peak (in the 100 data point array from the current iteration) by the time interval between data points (obtained using the Get Waveform Components Function). This number is then added to the total time which has passed since the LabVIEW program began running. This number is found by multiplying the number of loop iterations (found using the iteration loop iteration count indicator) by 100 (because there are 100 data points per loop) and then dividing the resulting number by the sampling rate, 1000 Hz. Adding the two times gives the true time point at which the recorded hammer signal occurred. (Figure 34)

Figure 34: Calculation of Elapsed Time Based on the Number of Loop Iterations

5. In order to save hammer time data points, we have a for loop that filters out unrelated data. Within this for loop, only time points above zero are recorded. Additionally, the for loop implements a method to check whether both an EMG signal and a hammer signal are recorded. If a hammer time value is recorded but no EMG time was recorded or vice versa, the data is deleted. This is all accomplished with a series of case structures (Figure 35).

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Figure 35: Measurement and Recording of the Hammer and EMG Times with Additional Filter,

Reset, and Remove Measurement Functions

EMG Signal 6. Similarly the EMG signal is acquired. Using the Filter Express VI, the 60 Hz (power line)

noise is filtered with a bandstop (notch) filter (Figure 36).

Figure 36: EMG Signal Filtration of 60 Hz Noise Using a Bandstop Filter in the Filter Express

VI

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7. The filtered signal is then converted from dynamic data to a waveform so that the peak

detector can read it. 8. Again, the EMG signal has an inherent noise even when the patient is not moving (at

rest). Therefore, a Threshold Detector VI is used so that only EMG values above the threshold value are recorded (Figure 37).

Figure 37: EMG Signal Detection Using a Threshold Detector VI and a Peak Detector VI

9. This EMG threshold value is derived from the value of the EMG signal when the patient is flexing their leg. When the patient is flexing their leg, they can press the calibrate button. When the button is activated, the case structure is true and it records the EMG value and halves it. This value is then input as the threshold for the Threshold Detector VI (Figure 38).

10. If the EMG threshold value is not calibrated, the threshold will be set to a default value of 0.05. The user can also manually input a specific threshold value (Figure 38).

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Figure 38: EMG Signal Threshold Calibration/Setting of Manual and Default Threshold Values

11. Steps 4 and 5 above are repeated for the EMG signal.

Reflex Time 12. When both an EMG and hammer time are recorded, the reflex time is calculated with

equation 6.

ef lex T ime EMG T ime Hammer T ime R = − Equation 6

Saving Data to Excel File 13. Finally, the data in the arrays can be written to Excel files using the Set Dynamic Data

Attributes Express VI and the Write To Measurement File Express VI (this excel file includes patient information and the time/date (Figures 39 and 40).

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Figure 39: Export Measured Values with Inputted Patient Information and Time/Date

Figure 40: Input Patient Information and Time/Date Section

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Additional Features for Ease of Use In order to improve the ease of use of this device, the LabVIEW front panel includes a button that opens up the user manual as a PDF for easy access (Figure 41).

Figure 41: Feature that Opens the User Manual as a PDF

This device also has pop-up feedback messages that confirm whether or not the calibration or Excel export was successful (Figures 42 and 43). The user can press the help buttons throughout the front panel to see answers to commonly asked questions (Figures 44 and 45). See Appendix

Figure 42: Feedback Message After Successful Calibration

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Figure 43: Feedback Message After Successful Excel Export

Figure 44: Pop-Up Answer to Frequently Asked Question for the Calibration Section of the

Device

Figure 45: Pop-Up Answer to Frequently Asked Question for the Reflex Time Indicator Section

of the Device

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Challenges & Limitations The EMG device is useful for many applications. However, it is limited by the nature of the body. The nervous system is an extensive and complicated network of nerves. Therefore, 11

surface EMGs will experience a lot of noise from different muscle groups that are activated in a single movement. Correct electrode placement is crucial for attenuating an accurate signal. However, it is difficult to regulate electrode placement as every human has unique anatomy which will change the optimal electrode placement. Lastly, the EMG device is only useful on skeletal muscle. 12

The EMG device is also limited by its hardware. Although our device does implement filters to try to reduce noise, not all of the noise is removed. The device has inherent electrical noise due to the electrical components in it. The device also picks up ambient noise caused by electromagnetic radiation. The human body constantly emits electromagnetic radiation so it is not possible to avoid this noise. Motion in the device also creates noise. Any movement of the 13

banana cables will distort the acquired signal. The overall accuracy of the measured EMG signal is definitely affected by these sources of noise.

11 “How Does the Nervous System Work?” National Center for Biotechnology Information, U.S. National Library of Medicine, 19 Aug. 2016, www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072574/. 12 Raez, M.B.I., M.S. Hussain, and F. Mohd-Yasin. “Techniques of EMG Signal Analysis: Detection, Processing, Classification and Applications.” Biological Procedures Online 8 (2006): 11–35. PMC. Web. 9 Nov. 2017. 13 Chowdhury, Rubana H. et al. “Surface Electromyography Signal Processing and Classification Techniques.” Sensors (Basel, Switzerland) 13.9 (2013): 12431–12466. PMC. Web. 9 Nov. 2017.

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Appendices EMG Device Protoboard

Figure 46: Overall EMG Device Protoboard with the all of the Circuits Described throughout

this User Manual/Technical Specifications Report

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Overall LabVIEW Block Diagram

Figure 47: Left Half of the Overall LabVIEW Block Diagram

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Figure 48: Right Half of the Overall LabVIEW Block Diagram

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