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UNIVERSITY OF DAR ES SALAAM

COLLEGE OF ENGINEERING AND TECHNOLOGY

DEPARTMENT OF CHEMICAL AND MINING ENGINEERING

CP499: FOURTH YEAR FINAL PROJECT

TITLE: DEVELOPMENT OF A SIMPLIFIED DATA ACQUISITION SYSTEM

FOR CME LABORATORY.

NAME OF STUDENT: MARO, ROLLAND D.

REGISTRATION NUMBER: 2013-04-01965.

ACADEMIC YEAR: 2016/2017.

DEGREE PROGRAMME: BSc. CHEMICAL AND PROCESS ENGINEERING

NAME OF SUPERVISOR: DR. RAPHAEL ISINGO.

SUBMISSIONS DATE: 04thJULY 2017

SIGNATURE:

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DECLARATION

I, MARO,ROLLAND D, declare that this report is my own original work being a full description

of the fourth year project that I conducted as a partial fulfillment of the requirement of Bachelor

degree in Chemical and Processing Engineering at College of Engineering and Technology

in University of Dar Es Salaam and it has not been and will not be presented to any University

for award of a degree.

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ACKNOWLEDGEMENT I would like to express my deepest appreciation to JEHOVAH for good health, strength and the

ability to do this project.

A special gratitude goes to my supervisor Dr. R Isingo for his guidance and contribution in

stimulating suggestions which helped me especially during writing this report.

I would like to thank the laboratory technician Mr. Mwakasege for assistance for providing

information which is essential for this project.

Last appreciation goes to the department of Chemical and Mining Engineering and all my fellow

students for the encouragement and all the help they gave me, their opinions and suggestions are

worth noting.

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ABSTRACT Laboratory training is an important part of every program from the CME department. But the

equipment at the CME laboratory are old and can’t cope with the current technology. Therefore

this project focuses in improving methods of data collection by introducing a simplified data

acquisition system for collecting data form lab experiments.

In this project a choice of two experiments from the laboratory is made and a simple system is

developed according to required measurements. The developed system is to measure flow rate,

temperature and mass.

The report consist of five main parts: introduction which also consist of problem statement and

objectives, literature review, methodology, development of the system and experimentation.

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Contents  

DECLARATION ............................................................................................................................ ii  

ACKNOWLEDGEMENT ............................................................................................................. iii  

ABSTRACT ................................................................................................................................... iv  

ABBREVIATION ........................................................................................................................... 1  

1.0   INTRODUCTION ............................................................................................................... 2  

1.1 INTRODUCTION TO CME LABORATORY. ................................................................... 2  

Current condition at CME lab ..................................................................................................... 2  

1.2 DATA ACQUISITION SYSTEM ........................................................................................ 2  

1.2.1 DAQ SOFTWARE ........................................................................................................ 3  

1.2.2 DAQ HARDWARE ....................................................................................................... 3  

1.2.3 SENSORS ...................................................................................................................... 3  

1.2.4 SIGNAL CONDITIONING. .......................................................................................... 4  

1.2.5 DATA TRANSMISSION .............................................................................................. 4  

1.2.6 DATA STORAGE ......................................................................................................... 4  

1.3 PROBLEM STATEMENT ................................................................................................... 5  

1.4 MAIN OBJECTIVES ........................................................................................................... 5  

1.5 SPECIFIC OBJECTIVES ..................................................................................................... 5  

1.6 SIGNIFICANCE OF THE PROJECT .................................................................................. 6  

2.0   LITERATURE REVIEW .................................................................................................... 7  

2.2 THE SCOPE OF THIS PROJECT ..................................................................................... 10  

3.0 METHODOLOGY ................................................................................................................. 10  

3.1   INVESTIGATION OF BRIQUETTES ......................................................................... 11  

3.3 DRYING ............................................................................................................................. 12  

3.3.1 REQUIREMENTS AND INSTRUMENTS. ............................................................... 12  

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3.3.2 DATA ACQUISITION SYSTEM ............................................................................... 12  

3.3.3 EXPERIMENTATION ................................................................................................ 12  

3.3.4 CALIBRATION .......................................................................................................... 13  

3.4   ERROR ANALYSIS ...................................................................................................... 13  

4.0   DAQ SYSTEM COMPONENTS ...................................................................................... 14  

4.1   SENSORS ...................................................................................................................... 14  

4.2   SIGNAL CONDITIONING ........................................................................................... 15  

4.3   DATA TRANSMISSION AND STORAGE ................................................................. 15  

5.0   DAQ SYTEM INTEGRATION ........................................................................................ 16  

5.1   Specifications of the system ........................................................................................... 17  

5.2   Operation of the system .................................................................................................. 17  

6.0   LABORATORY EXPERIMENTS .................................................................................... 18  

6.1   CALIBRATION OF THE EQUIPMENT ...................................................................... 18  

6.1.1   Temperature calibration .......................................................................................... 18  

6.1.2   Weight Sensor calibration ....................................................................................... 19  

6.2   INVESTIGATION OF BRIQUETTES ......................................................................... 20  

6.2.1   First briquettes samples ........................................................................................... 20  

6.2.2   Second briquette samples ........................................................................................ 21  

6.3   DRYING EXPERIMENT .............................................................................................. 22  

6.3.1   Rectangular object drying ....................................................................................... 22  

6.3.2   Cubic object drying. ................................................................................................ 23  

7.0   DISCUSSION .................................................................................................................... 24  

7.1   Recalibration of temperature sensor ........................................................................... 24  

7.2   Sensitivity of weigh scale ........................................................................................... 25  

8.0   CONCLUSION .................................................................................................................. 26  

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8.1   RECOMMENDATION ................................................................................................. 26  

References ..................................................................................................................................... 27  

APPENDIX A: DAQ system details. ............................................................................................ 28  

APPENDIX B: Experimentation raw data. ................................................................................... 29  

LIST OF FIGURES

Figure 1: General setup of data acquisition system. ....................................................................... 9  

Figure 2: Drying experiment setup. .............................................................................................. 12  

Figure 3: Integration of daq components. ..................................................................................... 16  

Figure 4: A complete daq system hardware. ................................................................................. 17  

Figure 5: Fire, Water and room temperature for Mkombozi briquette sample ............................. 21  

Figure 6: Fire, Water and room temperature for Siga Enterprises briquettes. .............................. 21  

Figure 9: Drying experiment ......................................................................................................... 22  

Figure 10: The drying curve of rectangular object. ...................................................................... 22  

Figure 11: The drying curve of rectangular object. ...................................................................... 23  

Figure 7: Daq system versus the industrial thermocouple. ........................................................... 24  

Figure 8: The relationship of the variation of the two thermocouple used. .................................. 25  

Figure 12: A detailed integration of daq components ................................................................... 28  

LIST OF TABLES

Table 1: Measurement summary table. ......................................................................................... 10  

Table 2: Fire, Water and room temperature for Mkombozi briquette sample .............................. 29  

Table 3: Raw drying data for rectangular object .......................................................................... 30  

Table 4: Raw drying data for cubic object .................................................................................... 31  

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ABBREVIATION

ADC - Analog to digital conversion.

CME - Chemical and Mining Engineering.

C++ - Programming language C plus plus.

DAQ - Data acquisition.

DC - Direct current.

I/O - Input/Output.

STHE - Shell and tube heat exchanger.

VI - Virtual Instrument.

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1.0 INTRODUCTION

1.1 INTRODUCTION TO CME LABORATORY.

Chemical and Mining Engineering (CME) laboratory provides experience from theoretical

studies by conducting experiments. This experience is essential for students and other research

work. In order to prove a theory behind an experiment, accurate data must be collected from a

controlled experimental conditions. This involves understanding the experiment before carrying

it.

Current condition at CME lab Equipment for practicing unit operations are available at the CME lab. Unit operations provides

a basic knowledge used in processing industries. But the equipment used in CME lab are old and

therefore can’t keep up with the current industrial technology. Thus the practice made in the lab

doesn’t satisfy the current requirements in experience needed by the industries.

Therefore the laboratory needs improvement of equipment. Data collection is one of the

important part that can be improved, and in this project data acquisition system will be

introduced to the lab. This will upgrade the technology of data collection in the lab.

A computer based data acquisition method will be introduced and incorporated to conduct

experiments in the CME lab. Three experiments from CME lab are used for application of data

acquisition system. These experiments are double pipe heat exchanger, drying and Falling film

Evaporator.

1.2 DATA ACQUISITION SYSTEM

Data acquisition (DAQ) is the process obtaining signals from sensors measuring real world

physical condition, digitizing the signals for storage, analysis and their presentation (Halvorsen,

2016). Therefore data acquisition system consists of sensors, signal conditioning circuit, DAQ

hardware for processing the signal and a computer with a software for analysis and presentation

of the result.

The analog to digital conversion function is included in the DAQ hardware and therefore there is

no need for another such hardware. Also the DAQ hardware serves as a bridge/ interface

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between sensor and computer because it has data transfer protocol for the computer port system.

Therefore it is an I/O device.

1.2.1 DAQ SOFTWARE

DAQ software is needed to integrate the hardware function with a pc. The different software are

classified due to their functions and specification such as configuring channels, logging and

displaying data.

Also there are programs that are general purpose like as c++, Visual c++ and basic. These

programs requires more programming skills.

Lastly there are programs that targets a certain area of application for example labview and

dasyab focuses on test, measurement, and control functions while matlab focuses on technical

computing and modelling.

(IDC Engineers, 2012).

1.2.2 DAQ HARDWARE

The function of this device is to digitize the incoming analog signals so that the computer can

interpret or store them. At the CME lab these device are currently not available. There are three

basic types of DAQ hardware

1) DAQ devices plugged on computer motherboard.

2) DAQ devices plugged using usb port and the supporting software running on computer

and

3) DAQ devices in which the software is first developed on a computer and later

downloaded to the device.

Usb plugged device will be favoured in this project due to its portability. In order for any of

these devices to be recognised and function, a computer driver for the device is installed

accordingly.

1.2.3 SENSORS

Sensors converts the physical process parameter of interest into a voltage or current that can be

processed by the controller. At the CME laboratory there exists a number of equipment which

have sensors integrated to them. The following are the equipment and their integrated sensors:

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Falling film evaporator; this equipment has sensors integrated for temperature sensing, pressure

and flow rate measurement. The function of this equipment is concentrating of aqueous solution

by vaporizing excess water. During the experiment pressure, temperature, flow rate of feed and

condensing vapour are monitored and their values are collected at different runs.

Heat exchanger; it has temperature sensors and pressure differential flow sensors. In this

experiment overall heat transfer in a double pipe heat exchanger is investigated and the

parameters monitored are steady state temperature and flow rates.

Dryer has thermocouples for temperature measurement. Flow rate of drying air, wet and dry bulb

temperature and weight loss of the drying samples are recorded.

Also there is a pneumatic temperature control in which temperature control sensors are

incorporated and a pneumatic valve is used as a final control element.

1.2.4 SIGNAL CONDITIONING.

This is the process of manipulating an analog signal in a way that prepares it for the next stage of

processing (Lee, 2011). Signal conditioning is grouped in three; filtering, amplifying and

isolating.

In filtering the purpose to remove unwanted noise from the signal, low pass, high pass and band

filter circuits are used in this process. Amplification process involves increasing resolution of a

signal so that it can be better interpreted by increasing signal to noise ratio. And lastly Isolation

is useful when the signal needs to be transmitted without a physical connection. It involves

converting the signal into other forms like frequency.

1.2.5 DATA TRANSMISSION

There are two modes of communication through which a peripheral data acquisition hardware

can interact with a computer. These are serial port connection and parallel port connection. In

serial connection data is sent at one bit at a time while in parallel connection multiple bits of data

can be sent and received simultaneously.

1.2.6 DATA STORAGE

The obtained data can be stored in the computer hard drive or portable devices such as memory

cards; such function is achieved by using a data logger. This is a device that saves data from the

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data acquisition hardware to the inserted memory card in a text file. The text file can later be

exported to excel for further processing.

For further processing programs like labview, matlab and dasylab has an exporting feature in

which data can be exported to excel for further processing and analysing of data.

1.3 PROBLEM STATEMENT

During the laboratory practical trainings plagiarism is a big problem among university students.

Students cheat by doing analysis of experiments using data from a different source and not the

conducted experiment. The presented reports reflects the problem. Most preferred sources are

reports from previous semesters, fellow students and internet. Therefore the objective of these

experiments is not realized as students do not acquire the necessary competence.

Difficulty in collecting accurate data in a controlled conditions is another contributing factor.

Thus mostly the collected data does not describe the investigated process correctly. This problem

is a primary cause of plagiarism. When the collected data doesn’t match the properties of the

investigated system, for the sake of grade students tend to find another source that is reliable and

matches the problem.

Not only at the educational sector but also the industrial sector Human errors causes the process

to run poorly and therefore the quality of products produced by this process are poor and thus are

the revenue obtained from such products.

1.4 MAIN OBJECTIVES

The objective of this project is to develop and a simple data acquisition system to improve data

collection at CME laboratory.

1.5 SPECIFIC OBJECTIVES

In order to achieve the main purpose the following specific object gives will be addressed.

1) To determine DAQ system components that are reliable.

2) To integrate the components so as to get a working system.

3) Incorporate the system for laboratory experiments measurement and analysis.

4) To compare data errors between physical method and data acquisition system.

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1.6 SIGNIFICANCE OF THE PROJECT This project exercises a part of data collection and analysis. The information collected from the

system can be used to control a process manually or using another control elements. Also it will

enhance the learning process in laboratory through accurate data collection and reflection of the

real system characteristics as they happen.

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2.0 LITERATURE REVIEW

Project title Project details Findings

Real-Time Data

Acquisition for

Shell and Tube

Heat Exchanger

(Paul, Shreesha,

& Shinde,

2015)

Equipment.

Shell and tube heat exchanger system is constructed using

32 copper tubes and a carbon steel shell, single pass, tube

length 750 mm and shell diameter 150mm.

Sensors and DAQ hardware.

Differential Pressure Transmitters, resistance temperature

detector.

What was done in this project.

In this project the process of interfacing Shell and Tube

Heat exchanger (STHE) with a PC through DAQ card is

presented. Data acquisition system consists of analog to

digital converter (ADC), digital to analog converter (DAC)

and a microcontroller. A LabVIEW program has been

developed to run the hardware as well as to capture the data.

LabVIEW platform has been used to produce a graphical

view of the user interface. A serial communication channel

is used to interface the PC with the DAQ card and the

signals from the plant are acquired to the PC. The

STHE VTPA-H-353 is a versatile and reliable computer

based temperature process controller. A graphical program

has been developed for the real time data acquisition from

the experiment using microcontroller based data acquisition

hardware unit.

Proposed Improvement

Improved DAQ hardware with integrated analog to digital

and digital to analog converters should be used to increase

portability of the system.

In this project

the method of

data acquisition

using labview

is successfully

presented.

Instrumentation

and Data

In this project three experiments using data acquisition are

done. The experiments done are: Dc motor drive system, a

Data

acquisition

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Acquisition

Projects

by Sophomore-

Level EET

Students

(Colosimo,

Kehoe, &

Naylor, 2004)

liquid level control system and environmental automation

system.

Equipment

A DAQ board model 6024E, signal conditioning element

Model SC-2075 all from national instruments and a desktop

signal breakout board.

Dc motor drive.

Performance evaluation of the DC motor was conducted in

this experiment. The motor was connected to a variable

frequency supply drive to get different torques.

What was done in this project

The lab View plots were obtained and from it can be seen

that for a given load, the relationship between speed drop

and loading is approximately linear and efficiency of the

motor is increasing with increasing load since the no-load

loss is significant for this ¼ hp

motor

Liquid level control system project.

Equipment used for this project were: A submersible pump,

and a level sensor made by a float hooked up to a

potentiometer

DAQ card receives two inputs (flow sensor

output and current sensor output) and provided two

outputs (light indicator and buzzer).

Block diagram

Environmental automation system project

The objective was implement a computer controlled

environmental automation system where by temperature and

lighting inside an enclosed chamber were controlled. This is

applicable in zoo and green houses.

techniques

were

implemented in

all three

projects and

Virtual

Instrumentation

programs were

presented.

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Equipment used

Lab View VIs was used for the end user interface, an

amplifier, DAQ card, thermocouples, light sensors, heater.

What was done in this experiment

The DAQ card altogether receives five analog input signals:

two amplified thermocouple signals, two light sensor

signals, and one reference temperature signal

From the projects reviewed the basic setup of can be concluded. The setup includes sensors,

signal conditioning circuit, and a controller. A computer or a data logger can be used for

presentation of the acquired data but most of the reviewed experiments used a computer system.

Figure 1: General setup of data acquisition system.

What will be done

Because of the nature of experiments carried out in the lab an option of using a data logger will

be favored so as to ease the process of commissioning and starting an experiment. Therefore the

use of a computer and a software is not necessary.

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2.2 THE SCOPE OF THIS PROJECT In this project the DAQ system will be developed within the provided budget. The system will

then be used to perform selected experiments in the laboratory. Process control will not be done

in this project but only acquiring data.

3.0 METHODOLOGY On this section what will be done in order to achieve the objectives will be presented. This

section is divided in to three experiments that will be performed.

The following table shows the parameters to be measured and the sensors used to measure them.

Table 1: Measurement summary table.

S/N Measurement variable Sensor Range

1 Temperature Thermocouple(K-type) -250°C-1250°C

2 Mass Electronic load cell 0 – 1 Kg

3 Flow rate Hall Effect Flow meter 1 – 30 Litres/min

A controller used is Arduino UNO microcontroller which has 13 digital pins which can be used

as inputs or outputs, 5 analog inputs and 6 analog outputs. The microcontroller is famous for

development project because of its low cost and easy to program.

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3.1 INVESTIGATION OF BRIQUETTES

In this experiment the aim was to investigate the composition of briquettes and determining the

efficiency of stove.

3.1.1 REQUIREMENTS AND INSTRUMENTS

The requirements of this experiment is a stove, weighing scale, a pan for boiling water,

thermocouples for measuring temperature and a reference industrial thermocouple.

3.1.2 DATA ACQUISITION SYSTEM

Figure 2: Briquettes investigation experiment setup

E-1

T

I-1

T

I-2

S-1

S-2

S-3

T

I-3

I-4

I-5

S-4

E-1: Stove and potI-1: Fire thermocoupleI-2: Water thermocoupleI-3: Sorrounding temperature thermocoupleI-4,5: Micro controller, computer

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3.3 DRYING In this experiment relationship between drying rate and moisture content is investigated.

Parameters monitored during the experiment are velocity and temperature of air, weight and

temperature of sample.

3.3.1 REQUIREMENTS AND INSTRUMENTS.

The temperature sensors used in this experiment are thermocouples, therefore the signal

conditioning is the same as in heat exchanger, anemometer for air velocity and electronic scale

for weight measurement.

3.3.2 DATA ACQUISITION SYSTEM

The following is the block diagram for the system.

E-1

I-1

T

I-2

E-2

W

S-1

S-2S-3

I-4 I-5

S-4

I-6

S-5

P-1 P-2I-1 anemometerI-2 thermocoupleI-4 data acquisition hardwareI-5 computerI-6 data logger.P-12 Electronic balance

Figure 3: Drying experiment setup.

3.3.3 EXPERIMENTATION

The procedures for obtaining data are as follows: (Raphael L, 1992)

1. The sample is initially weighed while dry and when soaked.

2. At a certain air velocity, weight and temperature of the sample is recorded at equal

intervals of time in the range of 5-10 minutes.

3. The acquired data is logged into the data logger or computer for analysis.

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3.3.4 CALIBRATION

The process of establishing mapping a scale in temperature measurement is done in the heat

exchanger experiment. The calibration of a weighing digital scale is done using standard mass

whose weight value is known.

The following table shows the summary of all variables that will be measured for all

experiments, their corresponding measurement sensors and their range of measurement.

3.4 ERROR ANALYSIS To determine the best method of data collection between the physical method and the data

acquisition system error analysis must be done.

The experiments will be done with four replications and ANOVA will be used to analyse the

errors. The sum of square from the Anova table shows the total variation that is caused by

variation of factors. The software that will be used for error analysis is Minitab version 17.

In the double pipe heat exchanger the varying factor is flow rate of cold and hot streams and the

observed response is temperatures. Several runs for the experiments will be done in order to get

the replication.

In the falling film evaporator the varying factor is temperature of feed and the response is flow

rate of concentrate.

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4.0 DAQ SYSTEM COMPONENTS

4.1 SENSORS

The following are the sensors that are used in the daq system

Sensor Specification Image Temperature thermocouple.

It is a K type thermocouple with a Chromel

{90% nickel and 10% chromium} Alumel {95%

nickel, 2% manganese, 2% aluminium and 1%

silicon} junction.

It is has a temperature range of 0 to 800°C. It

resistive to oxidation at higher temperatures but

vulnerable to sulphur attacks.

Weighing Load cell

The load cell used has two strain gauges. Strain

(a planar resistor) deforms/stretches/contracts

when the material of the load cells deforms

appropriately. The limit for the strain gauge used

is 5 Kg.

Exceeding this limit will cause the load cell to

deform permanently

Flow sensor Hall effect flow meter

The hall-effect flow sensor outputs

approximately 4.5 pulses per second per

litre/minute of flow.

The pulses increases with an increase in the flow

rate and the maximum flow rate is 30 L/min.

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4.2 SIGNAL CONDITIONING

Conditioning circuitry

Description Image

Thermocouple MAX6675

The MAX6675 performs cold-junction

compensation and digitizes the signal from a

type-K thermocouple. The data is output in a 12-

bit resolution.

It resolves temperatures to 0.25°C, allows

readings as high as +1024°C. The chip can alos

detect an open thermocouple.

Load cell HX711

By connecting the amplifier to the

microcontroller the changes in the resistance of

the load cell can be read, and with some

calibration very accurate weight measurements

are obtained.

4.3 DATA TRANSMISSION AND STORAGE Device Description Image Shift register CD4021BE

This device is used to convert a parallel input to

a serial output and thus it enables use of less

input pins in the micro controller.

It a 8 bit static shift register and therefore

converts 8 parallel input to serial transfer.

Micro Controller Arduino Uno The microcontroller is used to link all

components, get the digital data from all ADCs,

process them and store them in the memory

card.

It also distributes power to all of the sensors

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Micro SD memory card shield module.

The communication between the

microcontroller and the SD card uses SPI. The

functions of the module is:

Formatting and preparing the memory card.

File naming.

Opening and closing files

5.0 DAQ SYTEM INTEGRATION

The integration of the system is done using the above chosen parts. Integration is done first using

simulation by Proteus Isis design suite for configuring the arrangement of electronic components

and developing a program that will be used for the device. The following block diagram shows

the general method used in the integration of the daq system.

A more detailed drawing showing how to connect the components is shown in the appendix

under

Figure 4: Integration of daq components.

Reg

iste

r

Temperature ADC

Micro controller

Temperature ADC

Temperature ADC

Temperature ADC

SD card module

Weight ADC

Flow sensor

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The detailed integration of the components and program used is shown in the appendices 2.

The complete device is shown in the following pictures.

Figure 5: A complete daq system hardware.

5.1 Specifications of the system

• The system has 2 buttons a reset button denoted by number 1 on the image and a

start/stop button (6).

• The device can be powered in three ways: first is through a usb cable (2), second is

through a 9Volts dc battery, and lastly is through a 6 to 12 volts adapter (3).

• The system has 4 temperature channels but can be expended to 8 channels (there are free

slots for temperature ADC inside on number 9).

• The minimum time between sampling of data is 4 seconds.

• The device will tear the weighing scale each time it is stopped, reset or powered up.

• The tearing scale has an ability to accommodate a 3 bridge load cell which is more

accurate.

• The can only accommodate type K thermocouple and has an ability to measure

temperature at scale of 0 t0 1024°C.

5.2 Operation of the system

• A memory card is inserted into a memory card slot denoted by number 4 before starting

the device.

• Power is then turned on using a switch denoted by number 8.

1 2

3

4

5 6 7

8

9

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• After 5 seconds a led indicator should turn on showing the device is initialized correctly

and every component is connected ready to start sampling.

• To start taking data button number 6 is pressed briefly and once. Th led indicator will

start to pulsing showing data is taken. The time between pulses is the rate of sampling.

• To stop taking data the same button is again pressed once.

6.0 LABORATORY EXPERIMENTS

6.1 CALIBRATION OF THE EQUIPMENT

Parameters that are calibrated in the daq system are temperature and weight. The flow sensor has

a pre calibrated library and therefore doesn’t need calibration.

6.1.1 Temperature calibration

The process of calibrating the thermocouple (type K) sensor was done using a liquid in glass

thermometer with a range of 0 to 200°C. A linear curve is fitted to the data to obtain the best

approximation as shown in the figure below.

Thus the calibrating equation used to convert the instrument value to approximate temperature is

T ℃ = 0.2493x    where  x = instrument  reading.

y  =  0.2493x  R²  =  0.99627  

0  

50  

100  

150  

200  

250  

0   100   200   300   400   500   600   700   800   900  

Thermom

eter  re

ading  °C  

Instrument  reading    

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6.1.2 Weight Sensor calibration

The calibration of weight scale is done using 4 standard masses: 100 g, 200g, 500g and 1000g. A

linear curve is fitted to the data to obtain the best approximation as shown in the figure below.

Thus the calibrating equation used to convert the instrument value to approximate temperature is

Mass(g) = 0.3245x− 29615.8707  where  x = instrument  reading.

y  =  0.3245x  -­‐  29,615.8707  

0  

200  

400  

600  

800  

1000  

1200  

91000   91500   92000   92500   93000   93500   94000   94500  

Mass  (gram

s)  

Raw  instrument  reading  

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6.2 INVESTIGATION OF BRIQUETTES

The investigation of briquettes is done by starting with a fixed amount of water 2 litre. Burning

was done until all briquettes was converted into ashes. The following graphs represents the

burning of briquettes.

6.2.1 First briquettes samples

This briquette sample was from Mkombozi. The highest temperature obtained here was 700°C

for fire temperature.

0  

100  

200  

300  

400  

500  

600  

700  

800  

0   20   40   60   80   100   120   140   160  

Tempe

rature  (C

enJg

rade

)  

Time  (mins)  day  1  fire  temperature   waater  temp   sorrounding  temperature  

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Figure 6: Fire, Water and room temperature for Mkombozi briquette sample

6.2.2 Second briquette samples

This briquette sample was from Siga. The highest temperature obtained here was 575°C for fire

temperature.

Figure 7: Fire, Water and room temperature for Siga Enterprises briquettes.

0  

100  

200  

300  

400  

500  

600  

0   50   100   150   200   250   300  

Tem

pera

ture

(cen

tigra

de)

Time  (mins)  

heaJng  data  day  2   water  temperature   sorrounding  temperature  

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6.3 DRYING EXPERIMENT

Figure 8: Drying experiment

In the drying experiment the variables that were measured were dry and wet bulb temperature of

the income air, temperature of outgoing air and weight of the dried solid.

6.3.1 Rectangular object drying

Figure 9: The drying curve of rectangular object.

25  

35  

45  

55  

65  

75  

85  

95  

105  

0.00   5.00   10.00   15.00   20.00   25.00   30.00   35.00  

Moisture  conten

t  %  

Time  (minutes)  

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6.3.2 Cubic object drying.

Figure 10: The drying curve of rectangular object.

17  

19  

21  

23  

25  

27  

29  

0.00   5.00   10.00   15.00   20.00   25.00   30.00   35.00  

Moisture  conten

t  %  

Time  (mins)  

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7.0 DISCUSSION

Temperature sensors shows a deviation at higher temperature which decreases when the

temperature is low. Therefore a correction factor was to be added.

7.1 Recalibration of temperature sensor

A briquette investigation was done by using the daq system and an industrial grade daq

hardware. The purpose of this experiment was to compare the reading of the device and that of

the industrial thermocouple. The following graph shows the trend of the two thermocouples; the

red line shows industrial thermocouple and the blue line shows the daq device.

Figure 11: Daq system versus the industrial thermocouple.

The following diagram shows the relationship between the two temperatures. The obtained

equation can be used to recalibrate the temperature by adding a correction factor at higher

temperatures.

From the figure below the equation obtained is

y  =  3E-­‐10x5  -­‐  8E-­‐07x4  +  0.0007x3  -­‐  0.002435x2  +  1.023x  

Substituting the calibrated equation without the correction factor 𝑦 = 0.2493  𝑥

𝑦 = 7.5  𝑥  10!!𝑥! − 2𝑥10!!𝑥! + 0.000175𝑥! − 0.002435𝑥! + 0.25𝑥

0  

100  

200  

300  

400  

500  

600  

700  

800  

900  

1000  

0   50   100   150   200   250  

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Where y =temperature in °C and X is the instrument reading

Figure 12: The relationship of the variation of the two thermocouple used.

7.2 Sensitivity of weigh scale

The weighing scale has shown a high variation during weight measuring. The variation can be

caused by the following factors:

• Variation of the voltage on the power source causing electrical noises.

• Air disturbances.

In order to reduce the sensitivity of the sensor an average of ten readings is taken. This has a

disadvantage of delaying the response of the sensor but the reading becomes more stable.

y  =  3E-­‐10x5  -­‐  8E-­‐07x4  +  0.0007x3  -­‐  0.002435x2  +  1.023x    

0  

200  

400  

600  

800  

1000  

1200  

0   100   200   300   400   500   600   700   800  

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8.0 CONCLUSION The main objective of this project was successfully fulfilled. This report has covered all the

important steps that were done during the development, construction and testing of the data

acquisition device. The system developed has an ability to measure 4 temperature channels, 1

weight measurement and 1 flow rate.

Information obtained in this part can be used in improving the system if needed.

8.1 RECOMMENDATION

A more sophisticated daq device should be developed that has more functionalities like display

and more sensing elements. The deficiency of tools in the CME laboratory can be solved by

making our own instruments and in turn our technology and skills grows.

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References Colosimo, M., Kehoe, G., & Naylor, B. (2004). Instrumentation and Data Acquisition Projects

by Sophomore-Level EET Students. Pennsylvania: American Society for Engineering

Education .

Halvorsen, H. P. (2016). Data Acquisition in LabView. Norway: University College of Southeast

Norway.

Lee, M. J. (2011). Signal Conditioning Circuit Design. Michigan: Michigan State University .

Paul, R., Shreesha, D., & Shinde, S. (2015). Real-Time Data Acquisition Using LabVIEW for

Shell and Tube . Singapore: ICFCT.

Raphael L, M. (1992). Chemical and Process Engineering Laboratory Manual. Dar Es Salaam:

University Of Dar Es Salaam.