TEXAS A&M UNIVERSITYElectrical & Computer Engineering

Multi-parameter

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Tester User Guide

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TEXAS A&M UNIVERSITY

Multi-parameter Tester User Guide

By: Team DosSamuel ReynaJoshua AustinRichard OlivoJason DeVout

Table of ContentsOverview....................................................................................1Device Diagram.........................................................................2Operation...................................................................................3To Turn On/Off...........................................................................3Measuring Temperature.............................................................4Measuring Pressure...................................................................5Measuring Water Conductivity...................................................5Measuring Speed (in RPM)........................................................7Troubleshooting and Calibration................................................8Temperature..............................................................................8Pressure.....................................................................................9Water Conductivity.....................................................................9Speed (in RPM).........................................................................9Battery Charging/Monitoring......................................................9Bill of Materials.........................................................................11Main Board...............................................................................11Pressure Sensor Board............................................................12Water Conductivity Circuit Board.............................................12Temperature Sensor Board.....................................................13Speed/RPM Sensor Board.......................................................13Battery Charging Board...........................................................13Battery Monitoring Board.........................................................14Ratings and Warnings..............................................................15Ratings.....................................................................................15Warnings..................................................................................15Appendix..................................................................................17Temperature Sensor Circuit Schematic...................................17Pressure Sensor Circuit Schematic.........................................17Water Conductivity Circuit Schematic......................................18Speed Sensor Circuit Schematic.............................................18Charging &Powering Circuit Schematic...................................19

Acknowledgements..................................................................20

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OverviewThis section presents the device needs and an overview of functionality.

his Multi-paramater Tester serves to ensure proper operation of various pieces of hospital lab equipment in low-resource settings.This is achieved by measuring four parameters: temperature, pressure, water conductivity, and

speed. It to be primarily used for the following:TTemperature

Refrigerators Incubators

Speed Centrifuges

Water Conductivity Distillers

Pressure Sphygmomanometer

It may also be used for devices other than the ones mentioned, so long as the guidelines in this manual are followed. By measuring these parameters technicians are able to determine if the piece of equipment is functioning properly and make adjustments accordingly. This prevents malfunction, inaccurate results, and ultimately loss of expensive medical equipment.

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Device Diagram

Figure 1 - Front of Multi-parameter Tester

Temperature and RPM sensors located at back of device; Water purity probe located at the top of the device.

OperationThis section ensures proper operation of device.

To Turn On/Off

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Touch Screen

LED Battery Indicators

Power Switch

Power LED Charging LEDPressure Sensor

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To turn device on, locate the power switch on the front of the device and switch to either power source.

Figure 2 - Power Switch at Replaceable Battery position

By switching to the left side, the device uses the rechargeable batteries to run, while switching to the right side allows device to be powered by the AA replaceable batteries. To power off, simply move the switch back to the middle.

Once device is turned on, the touchscreen will display the main menu as shown below:

Figure 3 - Main menu

To choose parameter to be measured, press firmly on the virtual button on screen indicating that parameter.

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Measuring TemperatureTo measure temperature, press button on main menu reading ‘Temp’. The screen will now change to indicate the temperature in the default unit (Fahrenheit) received from the sensor located on the back of the device.

Figure 4 - Temperature Screen

The ambient temperature will be displayed in units of Fahrenheit and Celsius. To go back to the main menu, press the ‘Back’ button on the lower left corner of the screen.

For a proper temperature reading, place the device inside the environment to be measured for at least 5 seconds.

Measuring PressureFor measuring pressure, press button on main menu indicating ‘Press’. The screen will now change to indicate the pressure in units of mmHg received from the sensor at the front of the device.

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Figure 5 - Pressure Screen

To obtain a proper pressure reading, make sure rubber tube being used for calibration fits snugly onto the pressure sensor.

To go back to the home screen, press the lower left corner of the screen.

Measuring Water ConductivityTo measure water conductivity (for purity), press button on main menu indicating ‘H2O’. The screen will now change to indicate the status of water conductivity/purity being sensed by the probe.

Unwind probe cable from side of device. Place probe in the water to be tested, until it is completely submerged. Maintain probe in this position for at least 5 seconds to obtain a proper reading of the sample. Once status of water is given, remove the probe from the water, dry with a cloth and securely wind cable back onto cable holders.

WARNING:

The water conductivity probe looks like a standard two-prong wall plug; however, it does not supply power. DO NOT ATTEMPT TO PLUG PROBE INTO WALL OUTLET. DOING SO MAY RESULT IN DEVICE FAILURE.

If the probe is not in water, the screen will change to indicate ‘Not in Water’.

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If screen indicates ‘Pass’, water being tested is pure/clean; distiller is working properly and water is good for use.

If screen indicates ‘Fail’, water being tested is unclean/dirty; distiller is not working, do NOT use water.

Figure 6 - Water Purity Screen demonstrating that probe is not in water

To go back to the home screen, press the lower left corner of the screen.

Measuring Speed (in RPM)To measure speed (in revolutions per minute), press button on main menu indicating ‘RPM’. The screen will now change to indicate the speed of the object being calibrated.

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Figure 7 - Screen showing a sample RPM

For a proper speed reading, ensure that the optical sensor located on the back of the device is directly on top of spinning object. Furthermore, to get the right speed, the object being measured (e.g. a centrifuge) should have only one section/strip of reflective material (or non-reflective if surface is metal) going from the center of the spinning object to the edge. Modifying this may cause a speed measurement higher than the actual speed of the object. Maintain device steady in this position until speed reading on the screen is stable/constant.

Once speed is measured, you may go back to the home screen by pressing the lower left corner of the screen.

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Troubleshooting and CalibrationFixing potential problems and ensuring correct measurement.

His device has been designed to give accurate measurements even in poor conditions; however, should the device begin failing at any time the following steps will aid in the repair of each sensor. To determine if any of

the sensors are malfunctioning, follow these guidelines:T

Pressure sensor should read about 40 mmHg (may be unstable due to noise) with no pressure from tube. If reading fluctuates too much from this, sensor circuit is malfunctioning.

If temperature shown on screen is obviously inaccurate (reads 170 ºF when it should be 70 ºF) then temperature sensor circuit must be adjusted/repaired.

If water conductivity reads ‘Not in Water’ while probe is in water, or reads ‘Pass’ for dirty water, troubleshooting must be done.

If screen shows a high speed when the RPM sensor is not measuring a spinning surface, the speed sensor circuit and algorithm must be checked.

TemperatureIf the temperature output is not working correctly, the first thing to do is to measure the resistance of the RTD. Unpowered, and near room temperature, the RTD should have a resistance of approximately 2000 ohms. The second step is to measure the incoming power to the sensor circuit board. Reference the schematic, and make sure that the three sources are the correct value. If one of the voltages is incorrect, then the regulators need to be checked. Once the power has been observed to be correct, measure the voltage on the supply terminals of the operational amplifier and the instrumentation amplifier. The output of the sensor board can be calibrated by tuning the potentiometer on the top left side of the circuit board.

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PressureIf the pressure output is not working correctly, the first thing to do is to measure the resistance of the pressure sensor between the “Icc” and “GND” pins. Unpowered, the pressure sensor should have a resistance of approximately 20.000 ohms. The second step is to measure the incoming power to the sensor circuit board. Reference the schematic, and make sure that the three sources are the correct value. If one of the voltages is incorrect, then the regulators need to be checked. Once the power has been observed to be correct, measure the voltage on the supply terminals of the operational amplifier and the instrumentation amplifier. The output of the sensor board can be calibrated by adjusting the processing equation in the microcontroller software.

Water ConductivityIf the temperature output is not working correctly, the first thing to do is to measure the resistance of the probe. Disconnected from the circuit, the probe should be an open circuit and have an infinite resistance. The second step is to measure the incoming power to the sensor circuit board. Reference the schematic, and make sure that the two sources are the correct value. If one of the voltages is incorrect, then the regulators need to be checked. Once the power has been observed to be correct, measure the voltage on the supply terminals of the operational amplifiers. The first potentiometer in the schematic allows you to calibrate the Wien Bridge Oscillator that generates the AC waveform. The amplitude of the signal generated at the output of the first op-amp needs to be approximately 20Vpp. The third potentiometer sets the bias for the zero point pressure. Change the pot until the output at zero pressure is approximately zero.

Speed (in RPM)If the pressure output is not working correctly, the first thing to do is to make sure the phototransistor on the optical sensor still operates. Unpowered, the phototransistor should be an open circuit with zero voltage output. The second step is to measure the incoming power to the sensor circuit board. Reference the schematic, and make sure that the source is the correct value. If the voltage is incorrect, then the regulator needs to be checked. Once the power has been observed to be correct, measure the output voltage when a reflective surface is within a few millimeters of the sensor. The output of the sensor board can be calibrated by adjusting the processing equation in the microcontroller software.

Battery Charging/MonitoringIf the led indicators on the battery charging system do not turn on, or if the system does not seem to be powering the NiMH battery, check the voltage at the input of the Smart Charging Circuit board to see if the circuit is in fact

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receiving voltage. The Smart Charging Circuit is set to charge the NiMH battery at 500 mA. Disconnect the incoming voltage jumper from the PCB and place an ammeter in series with the jumper and ensure that the board is pulling 500 mA when charging. Second, measure the output voltage of the circuit to see if the voltage is indeed leaving the circuit. If the Smart Charging Circuit is not outputting proper voltage or current, replace the IC along with the two BJ Transistors.

If the battery monitoring system does not indicate the system’s voltage through the LEDs, check to see if the Monitoring PCB is receiving voltage. If the board is receiving voltage, check to see if all LEDs are connected to the board. If every component seems fine, then the IC may need to be replaced.

Bill of MaterialsList of parts for repair of device.

his section list all components of the device according to the individual PCBs found within the enclosure. All sensor, battery, and processing boards are attached to the main PCB board, which is fixed onto the enclosure with 4

clips. The temperature, speed, and water conductivity boards are found on the bottom of the board, while the remaining boards (including the microcontroller and screen) are found on the top side. Components with more than one of the same element are denoted with (#).

TMain BoardComponents:

NiMH Battery Pack: 14.4 V 2200mAh ( 31.68 Wh, 12xAA) Battery Holders, Clips & Contacts 10XAA TABS BLK Slide Switches Mini slide vertical actuator SP4T

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LM7805 +5V Voltage Regulator LM7812 +12V Voltage Regulator LM317T Adjustable Voltage Regulator (2) 755-BP5122 Negative DC/DC (-12V) Converter/Regulator 0.1 uF capacitors (5) 1 uF capacitors (6) 240 ohm resistor 430 ohm resistor 1.6 kohm resistor 82 ohm resistor DC PWR 2.1 MM Gray Kobiconn Connector for DC Power PCB 2.1 MM Kobiconn Connector Samsung Replacement 19V, 3.16 A 60W AC Adapter TI Stellaris LM4F120 LaunchPad Evaluation Board (EK-LM4F120XL) Kentec Display Stellaris LaunchPad LCD Boosterpack EB-LM4F120-L35

Pressure Sensor BoardComponents:

2SMPP-03 OMRON Pressure Sensor INA126PAMicroPOWER Instrumentation Amplifier IC LM1458N TI Dual OPAMP IC 2N2222 BJ NPN Transistor 1N4001 Diode TC54VC42 Microchip Voltage Detector 500 ohm resistor 10 kohm resistor 100 kohm resistor 1.4 kohm resistor 1 kohm resistor 100 ohm resistor

Water Conductivity Circuit BoardComponents:

LM1458N TI Dual OPAMP IC (3) 1N5227 Zener Diode, 3.6V 1N4148 Diode, GP Silicon (4) 2N2222 BJ NPN Transistor TC54VC42 Microchip Voltage Detector 0.22 uF capacitor 0.15 uF capacitors (2) 100 kohm potentiometer 2 kohm potentiometer 22 kohm potentiometer

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33 kohm resistor 1 kohm resistors (5) 100 kohm resistors (3) 56 kohm resistor 0.22 Mohm resistor 6.8 kohm resistor 22 kohm resistor 220 kohm resistors (3) 82 kohm resistor 2 kohm resistor 380 ohm resistor 200 ohm resistor 6.3 kohm resistor

Temperature Sensor BoardComponents:

INA126PAG4 MicroPOWER Instrumentation Amplifier IC LM1458N TI Dual OPAMP IC TD5A RTD Temperature Sensor 2N2222 BJ NPN Transistor TC54VC42 Microchip Voltage Detector 1N4001 Diode LM7805 +5V Voltage Regulator 50.5 kohm resistor (2) 7 kohm resistor 4 kohm resistor 9 kohm resistor 28 kohm resistor 68 kohm resistor 680 ohm resistor 6.3 kohm resistor 10 kohm potentiometer

Speed/RPM Sensor BoardComponents:

TRCT5000 Vishay Optical Reflex Sensor 15 kohm resistor 180 ohm resistor

Battery Charging BoardComponents:

2N4403 Fairchild PNP General Purpose Amplifier MAX712 NiCd/NiMH Battery Fast-Charge Controllers IC

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2N2222 BJ NPN Transistor 1N4001 Diode 10 uF capacitors (2) 1 uF capacitor 22 nF capacitor 150 ohm resistor 10 kohm resistors (2) 1 kohm resistor 2.2 kohm resistor 500 ohm resistor 33 kohm resistor 470 ohm resistor 0.3 ohm resistor Red LEDs (2)

Battery Monitoring BoardComponents:

LM3914 TI Dot/Bar Display Driver IC 56 kohm resistor 200 kohm potentiometer 10 kohm resistor Red LEDs (2) Yellow LEDs (3) Green LEDs (5)

Ratings and WarningsTaking proper care of device and preventing malfunction.

RatingsThis device was designed to accurately measure each parameter within the following ranges:

Temperature: 0°-100° C ( 0.1° resolution)

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Water Conductivity: 0 –99 uS

Pressure: 0-300 mmHg

Speed: 200-100,000 RPM (60 RPM resolution)

Attempting to measure any parameter beyond the above ranges may lead to inaccurate measurements or damage to the sensors.

WarningsGeneral:

1. DO NOT shake or throw device with excessive force. This may cause component damage and ultimately failure of device.

2. Keep device in a dry place at room temperature. Except for the water conductivity probe, device is not designed to be in wet or damp environment.

3. DO NOT press hard on touch screen or use sharp object to press the on the screen. Doing so may pierce it and leave it unusable.

Water Conductivity Probe:

1. DO NOT plug probe into wall outlet. Doing so may result in device failure.

2. Properly wind probe cable back onto holder to prevent cable from being stretched and detached from device.

3. Dry probe completely before winding it back to prevent other components from getting wet.

Temperature Sensor:

1. Avoid touching temperature sensor in the back of the device. Moving or touching sensor could cause improper readings and sensor malfunction.

2. Do not remove protective metal clip from enclosure. Doing so leaves temperature sensor vulnerable to bending/breaking.

Pressure Sensor:

1. When adjusting tube to pressure sensor, make sure to not press into sensor roughly in order to prevent sensor from being pushed into the enclosure.

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2. Keep sensor and surrounding area clean, any dirt/debris that falls inside the sensor may affect performance.

Speed/RPM Sensor:

1. Do NOT cover sensor when measuring the speed of an object. Doing so will prevent speed reading.

2. Do NOT place several reflective/non-reflective strips on surface of object being measured; this will cause the device to output a higher speed than what the object is actually spinning at.

AppendixTemperature Sensor Circuit Schematic

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Pressure Sensor Circuit Schematic

Water Conductivity Circuit Schematic

Speed Sensor Circuit Schematic

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Charging &Powering Circuit Schematic

(Continued)

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AcknowledgementsWe would like to acknowledge the Biomedical Engineering students involved in the design of this project: Mason Cote, Romina del Bosque, Hailey Marsh, and Jonathan Franks.

We would also like to acknowledge the graduate students assisting during the design process for their input: ShafeeqShajudeen from the Electrical Engineering Department and Kristen Duckworth from the Biomedical Engineering Department.

Furthermore, we would like to give a special acknowledgement to our faculty sponsors: Dr. Samuel Villarreal from the Electrical and Computer Engineering Department and Dr. Kristen Maitland, from the Biomedical Engineering Department.

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