“pH CONTROL IN A BIOREACTOR”

USING DAQ 6009

Project report submitted in fulfillment of the requirements

For the award of the degree of

BACHELOR OF TECHNOLOGY

IN

ELECTRICAL AND ELECTRONICS ENGINEERING

BY

S.KAMAL VISWANATH (07241A0206)

M.CHIRANJEEVI (07241A0231)

M.RAMESH (07241A0245)

K.SHRAVAN (07241A0247)

Under the guidance of

Sri.E.VENKATESHWARULU

Department of EEE

Department of Electrical and Electronics Engineering

Gokaraju Rangaraju Institute of Engineering & Technology

(Affiliated to Jawaharlal Nehru Technological University)

Hyderabad

2007 - 2011

GOKARAJU RANGARAJU INSTITUTE OF ENGINEERING AND

TECHNOLOGY

Hyderabad, Andhra Pradesh.

DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING

This is to certify that the project report entitled “pH CONTROL IN A

BIOREACTOR” that is being submitted by KAMAL VISWANATH, CHIRANJEEVI,

RAMESH, SHRAVAN, in partial fulfillment for the award of the Degree of Bachelor of

Technology in Electrical and Electronics Engineering to the Jawaharlal Nehru

Technological University is a record of bonafide work carried out by them under my

guidance and supervision. The results embodied in this project report have not been

submitted to any other University or Institute for the award of any Graduation degree.

Head of Department Project Coordinator Internal Guide

Prof.P.M.SHARMA Prof. S.N.Saxena Sri. E.Venkateshwarulu

Professor & HOD Professor Assistant Professor

EEE, GRIET EEE, GRIET EEE, GRIET

ACKNOWLEDGMENT

This is to place on record my appreciation and deep gratitude to the persons without

whose support this project would never seen the light of day.

I wish to express my propound sense of gratitude to Sri. P. S. Raju, Director,

G.R.I.E.T for his guidance, encouragement, and for all facilities to complete this project.

I have immense pleasure in expressing my thanks and deep sense of gratitude to my

guide Sri.E.Venkateshwarulu, Assistant Professor, Department of Electrical and

Electronics Engineering, G.R.I.E.T for his guidance throughout this project.

I also express my sincere thanks to Sri.P.M.Sarma, Head of the Department,

G.R.I.E.T and for extending their help.

I express my gratitude to Mr. S.N. Saxena, Professor, Department of Electrical and

Electronics Engineering, Coordinator, Project Review Committee, G.R.I.E.T for his

valuable recommendations and for accepting this project report.

Finally I express my sincere gratitude to Sri. M. Chakravarthy , Associate Professor,

Department of Electrical and Electronics Engineering, G.R.I.E.T and all the members of

faculty and my friends who contributed their valuable advice and helped to complete the

project successfully.

S. Kamal Viswanath (07241A206)

M. Chiranjeevi (07241A0231)

M. Ramesh (07241A0245)

K.Sharavan (07241A0247)

ABSTARCT

The aim of developing this project is to

automate the control of the pH of solution in a bioreactor. A bioreactor is a

vessel in which is carried out a chemical process which involves organisms or

biochemically active substances derived from such organisms. Under optimum

conditions the microorganisms or cells will reproduce at an astounding rate. So

the conditions like temperature, pH value, oxygen rate are to be maintained. The

main idea of the project is to amplify the voltage that is generated by the pH

sensor and send this voltage to a controlling component. This component is to

be selected such that two limits an upper and a lower limit can be set to it, by

which any change in the amplifier voltage beyond the limits an output signal is

to be generated by the control circuit. This signal will control the pH by adding

pH solutions to it. This project is practical and highly feasible in economic point

of view, and has an advantage of controlling the pH value in a wide range. This

project is an automated, reliable and adaptable way of controlling the pH value

in a bioreactor.

CONTENTS

Abstract II List of figures V List of Tables VI

Chapter 1. Introduction 1

1.1 Bioreactor 1 1.2 pH 3 1.3 pH sensor 4 1.4 Operational Amplifiers 7 1.5 DAQ 10

Chapter 2. Block Diagram 13

Chapter 3. Circuit Diagram 14

Chapter 4. System Simulation Results 15 Chapter 5. Hardware Description 17 5.1 Hardware Circuit 18

Chapter 6. Software Description 19

6.1 Multisim 19 6.1.1 Use of Multisim in this project 19

6.2 LabVIEW 21 6.2.1 Use of LabVIEW in this project 22 6.2.2 Interfacing with DAQ 22

Chapter 7. Outputs Observed 24

Chapter 8. Conclusion and Scope for future work 29

8.1 Conclusion 29

8.2 Scope for future work 29

References 30 Appendix A 31 Appendix B 32 Appendix C 37

LIST OF FIGURES

Figure no. Figure Name Page no.

1.1 Basic pH sensor 6

1.2 Basic op amp 8

1.3 DAQ 12

1.4 DAQ interfacing mechanism 12

2.1 Block Diagram of the project 13

3.1 Multisim Circuit 14

4.1 Multisim simulation output 16

5.1 Hardware 18

6.1 Maximum output voltage 20

6.2 Minimum output voltage 20

6.3 LabView layout 22

7.1 Practical input 1 24

7.2 Practical output 1 24

7.3 Practical input 2 25

7.4 Practical output 2 25

7.5 Below the limit output 26

7.6 Within the limit output 26

7.7 Above the limit output 27

List of tables

Table no. Table name Page no.

4.1 System simulation results table 15

7.1 Practical results table 28

CHAPTER-1

INTRODUCTION

pH control is the one of the most important aspect that is to be maintained in a bioreactor. This is achieved by a set of equipments and circuits. The main blocks of this project are:

• pH sensing device • Amplification circuit • Controlling device

By combining all these blocks the output is achieved which is to control the pH value in a bioreactor. The working of a project is better understood if explained in parts.

1.1 BIOREACTOR:

A bioreactor is a vessel in which is carried out a chemical process which involves organisms or biochemically active substances derived from such organisms. Bioreactors are commonly cylindrical, ranging in size from some liter to cube meters, and are often made of stainless steel. Bioreactor design is quite a complex engineering task. Under optimum conditions the microorganisms or cells will reproduce at an astounding rate. The vessel's environmental conditions like gas (i.e., air, oxygen, nitrogen, carbon dioxide) flow rates, temperature, pH and dissolved oxygen levels, and agitation speed need to be closely monitored and controlled. One bioreactor manufacturer, Bradley-James Corporation, uses vessels, sensors, controllers, and a control system, digitally networked together for their bioreactor system.

Cell culture bioreactors are categorized into two types: 1. those that are used for cultivation of anchorage dependent cells (e.g. primary cultures derived from normal tissues and diploid cell lines. 2. Those that are used for the cultivation of suspended mammalian cells (e.g. cell lines derived from cancerous tissues and tumors, transformed diploid cell lines, hybridomas). In some cases the bioreactor may be modified to grow both anchorage dependent and suspended cells. Ideally any cell culture bioreactor must maintain a sterile culture of cells in medium conditions which maximize cell growth and productivity.

Fouling can harm the overall sterility and efficiency of the bioreactor, especially the heat exchangers. To avoid it the bioreactor must be easily cleanable and must be as smooth as possible (therefore the round shape). The pH value of the substance is to be maintained constant.

Heat exchange is needed to maintain the bioprocess at a constant temperature. Biological fermentation is a major source of heat; therefore in most cases bioreactors need water

refrigeration. They can be refrigerated with an external jacket or, for very large vessels, with internal coils. Optimal oxygen transfer is perhaps the most difficult task to accomplish. Oxygen is poorly soluble in water -and even less in fermentation broths- and is relatively scarce in air (20.8%). Oxygen transfer is usually helped by agitation that is also needed to mix nutrients and to keep the fermentation homogeneous. There is however limits to the speed of agitation, due both to high power consumption (that's proportional to the cube of the speed) and the damage to organisms due to excessive tip speed. Bioreactor treatment may be performed using microorganisms growing in suspension in the fluid or attached on a solid growth support medium. In suspended growth systems, such as fluidized beds or sequencing batch reactors, contaminated groundwater is circulated in an aeration basin where a microbial population aerobically degrades organic matter and produces carbon dioxide, water, and biomass. The biomass is settled out in a clarifier, then either recycled back to the aeration basin or disposed of as sludge. In attached growth systems, such as up flow fixed film bioreactors, rotating biological contactors (RBCs), and trickling filters, microorganisms are grown as a biofilm on a solid growth support matrix and water contaminants are degraded as they diffuse into the biofilm. Support media include solids that have a large surface area for bacterial attachment.

Moisture content is the single most important factor that promotes the accelerated decomposition. The bioreactor technology relies on maintaining optimal moisture content near field capacity (approximately 35 to 65%) and adds liquids when it is necessary to maintain that percentage. The moisture content, combined with the biological action of naturally occurring microbes decomposes the waste. The microbes can be either aerobic or anaerobic. A side effect of the bioreactor is that it produces landfill gas (LFG) such as methane in an anaerobic unit at an earlier stage in the landfill’s life and at an overall much higher rate of generation than traditional landfills.

Bioreactors have a wide range of applications in various fields like

• Medicine: The immobilized enzyme reactors are one of the most recent achievements in the field of medicine.

• Environment : Water purification plants, sewage plant bioreactors, land filling bioreactors has bought a major change in the recycle of the waste in the environment Other than these advantages bioreactors find a wide range of applications in industries, research and food processing plants.

1.2 pH:

pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. pH measurements are important in medicine, biology, food science, environmental science, oceanography, civil engineering and many other applications. In a solution pH approximates but is not equal to p[H], the negative logarithm (base 10) of the molar concentration of dissolved hydronium ions (H3O+); a low pH indicates a high concentration of hydronium ions, while a high pH indicates a low concentration. This negative of the logarithm matches the number of places behind the decimal point, so, for example, 0.1 molar hydrochloric acid should be near pH 1 and 0.0001 molar HCl should be near pH 4 (the base 10 logarithms of 0.1 and 0.0001 being −1, and −4, respectively). Pure (de-ionized) water is neutral, and can be considered either a very weak acid or a very weak base (center of the 0 to 14 pH scale), giving it a pH of 7 (at 25 °C (77 °F)), or 0.0000001 M H+. For an aqueous solution to have a higher pH, a base must be dissolved in it, which binds away many of these rare hydrogen ions. Hydrogen ions in water can be written simply as H+ or as hydronium (H3O+) or higher species (e.g., H9O4

+) to account for solvation, but all describe the same entity. Most of the Earth's freshwater surface bodies are slightly acidic due to the abundance and absorption of carbon dioxide; in fact, for millennia in the past, most fresh water bodies have long existed at a slightly acidic pH level.

However, pH is not precisely p[H], but takes into account an activity factor. This represents the tendency of hydrogen ions to interact with other components of the solution, which affects among other things the electrical potential read using a pH meter. As a result, pH can be affected by the ionic strength of a solution – for example, the pH of a 0.05 M potassium hydrogen phthalate solution can vary by as much as 0.5 pH units as a function of added potassium chloride, even though the added salt is neither acidic nor basic.

Hydrogen ion activity coefficients cannot be measured directly by any thermodynamically sound method, so they are based on theoretical calculations. Therefore, the pH scale is defined in practice as traceable to a set of standard solutions whose pH is established by international agreement.

It is unknown what the exact definition of 'p' in pH is. A common definition often used in schools is "percentage". However some references suggest the p stands for “Power”, others refer to the German word “Potenz” (meaning power in German), still others refer to “potential”. Jens Norby published a paper in 2000 arguing that p is a constant and stands for “negative logarithm”; H then stands for Hydrogen. According to the Carlsberg Foundation pH stands for "power of hydrogen". Other suggestions that have surfaced over the years are that the p stands for puissance (also meaning power, but, then, the Carlsberg Laboratory was French-speaking) or that pH stands for the Latin terms pondus Hydrogenii or potentia hydrogenii. It is also suggested that Sorensen used the letters p and q (commonly paired letters in mathematics) simply to label the test solution (p) and the reference solution (q).

1.3 pH SENSORS:

A pH sensor is a typical transducer that senses the hydronium ion concentration which will be proportional to the pH value of the solution and produces a voltage proportional to the value of the pH. The pH sensor is a loop of components that senses and transmits the pH value.

1.3.1 Working:

A pH measurement loop is made up of three components, the pH sensor, which includes a measuring electrode, a reference electrode, and a temperature sensor; a preamplifier; and an analyser or transmitter. A pH measurement loop is essentially a battery where the positive terminal is the measuring electrode and the negative terminal is the reference electrode. The measuring electrode, which is sensitive to the hydrogen ion, develops a potential (voltage) directly related to the hydrogen ion concentration of the solution. The reference electrode provides a stable potential against which the measuring electrode can be compared.

1.3.2 Typical pH Sensor:

When immersed in the solution, the reference electrode potential does not change with the changing hydrogen ion concentration. A solution in the reference electrode also makes contact with the sample solution and the measuring electrode through a junction completing the circuit. Output of the measuring electrode changes with temperature (even though the process remains at a constant pH), so a temperature sensor is necessary to correct for this change in output. This is done in the analyser or transmitter software. The pH sensor components are usually combined into one device called a combination pH electrode. The measuring electrode is usually glass and quite fragile. Recent developments have replaced the glass with more durable solid-state sensors. The preamplifier is a signal-conditioning device. It takes the high-impedance pH electrode signal and changes it into allow impedance signal which the analyser or transmitter can accept. The preamplifier also strengthens and stabilizes the signal, making it less susceptible to electrical noise. The sensor's electrical signal is then displayed. This is commonly done in a 120/240 V ac-powered analyser or in a 24 V dc loop-powered transmitter. Additionally, the analyser or transmitter has a man machine interface for calibrating the sensor and configuring outputs and alarms, if pH control is being done. Keep in mind, application requirements should be carefully considered when choosing a pH electrode. Accurate pH measurement and the resulting precise control that it can allow, can go a long way toward process optimisation and result in increased product quality and consistency. Accurate, stable pH measurement also controls and often lowers chemical usage, minimising system maintenance and expense.

1.3.3 Keeping the System Up and Running: A system's pH electrodes require periodic maintenance to clean and calibrate them. The length of time between cleaning and calibration depends on process conditions and the user's accuracy and stability expectations. Overtime, electrical properties of the measuring and reference electrode change. Calibration in known-value pH solutions called buffers will correct for some of these changes. Cleaning of the measuring sensor and reference junction will also help. However, just as batteries have a limited life, a pH electrode's lifetime is also finite. Even in the "friendliest" environments, pH electrodes have to be replaced eventually.

1.3.4 Calibration and Use:

For very precise work the pH meter should be calibrated before each measurement. For normal use calibration should be performed at the beginning of each day. The reason for this is that the glass electrode does not give a reproducible e.m.f. over longer periods of time. Calibration should be performed with at least two standard buffer solutions that span the range of pH values to be measured. For general purposes buffers at pH 4 and pH 10 are acceptable. The pH meter has one control (calibrate) to set the meter reading equal to the value of the first standard buffer and a second control (slope) which is used to adjust the meter reading to the value of the second buffer. A third control allows the temperature to be set. Standard buffer sachets, which can be obtained from a variety of suppliers, usually state how the buffer value changes with temperature. The calibration process correlates the voltage produced by the probe (approximately 0.06 volts per pH unit) with the pH scale. After each single measurement, the probe is rinsed with distilled water or deionized water to remove any traces of the solution being measured, blotted with a clean tissue to absorb any remaining water which could dilute the sample and thus alter the reading, and then quickly immersed in another solution.

1.3.5 Types of pH Meters

A simple pH meter pH meters range from simple and inexpensive pen-like devices to complex and expensive laboratory instruments with computer interfaces and several inputs for indicatoreraturevariation in pH caused by temperature. Specialty meters and probes are available for use in special applications, harsh environments, etc.around 1936 by Radiometer in Denmark and byStates. While Beckman was an assistant professor of chemistry at theTechnology, he was asked to devise a quick and accurate method for measuring the acidity of lemon juice for the California Fruit Growers Exchangehelped him to launch the Beckman Instruments company (nowthe Beckman pH meter was designated anrecognition of its significance as the first commercially successful electronic pH meter.

Types of pH Meters:

A simple pH meter pH meters range from simple and inexpensive like devices to complex and expensive laboratory instruments with computer interfaces

and several inputs for indicatorerature measurements be entered to adjust for the slight variation in pH caused by temperature. Specialty meters and probes are available for use in special applications, harsh environments, etc. The first commercial pH meters were built

in Denmark and by Arnold Orville Beckman in the United States. While Beckman was an assistant professor of chemistry at the California Institute of

, he was asked to devise a quick and accurate method for measuring the acidity California Fruit Growers Exchange (Sunkist). Beckman's invention

Beckman Instruments company (now Beckman Coulterthe Beckman pH meter was designated an ACS National Historical Chemical Landmarkrecognition of its significance as the first commercially successful electronic pH meter.

A simple pH meter pH meters range from simple and inexpensive like devices to complex and expensive laboratory instruments with computer interfaces

measurements be entered to adjust for the slight variation in pH caused by temperature. Specialty meters and probes are available for use in

The first commercial pH meters were built in the United

California Institute of , he was asked to devise a quick and accurate method for measuring the acidity

). Beckman's invention Beckman Coulter). In 2004

ACS National Historical Chemical Landmark in recognition of its significance as the first commercially successful electronic pH meter.[2]

1.4 OPERATIONAL AMPLIFIERS (OPAMPS):

coupled high-gain electronic voltageended output. An op-amp produces an output voltage that is typically hundreds of thousands times larger than the voltage differenceare important building blocks for a wide range of electronic circuits. They had their origins in analog computers where they were used in many linear, nondependent circuits. Their popularity in circuit design largely stems from the fact the characteristics of the final elements (such as theirlittle dependence on temperature changesOp-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. Many standard IC opcents in moderate production volume; however some integrated or hybrid operational amplifiers with special performance specifications may cost over $100 US in small quantities. Op-amps may be packaged as components, or used as elements of more complex integrated circuits. The op-amp is one type ofdifferential amplifier include thetwo outputs), the instrumentation amplifieramplifier (similar to the instrumentation amplifier, but with tolerance to commonvoltages that would destroy an ordinary opbuilt from one or more op-amps and a resistive feedback network).

1.4.1Operation:

The amplifier's differential inputs consist of aideally the op-amp amplifies only the difference in voltage between the the differential input voltage. The output voltage of the op

where is the voltage at the nonterminal and AOL is the open-loopabsence of a feedback loop from the output to the inputvery large—10,000 or more for integrated circuit op

difference between and is called saturation of the amplifier. The magnitude ofmanufacturing process, and so it is impractical to use an operational amplifier as a standalone differential amplifier. If predictable operation is desired,applying a portion of the output voltage to the inverting input. The greatly reduces the gain of the amplifier. If negative feedback gain and other parameters become determined more by the feedback network than by the opamp itself. If the feedback network is made of components with relatively constant, stable values, the unpredictability and inconstancy o

IONAL AMPLIFIERS (OPAMPS):

An operational amplifier ("op-amp") is aelectronic voltage amplifier with a differential input and, usually, a single

amp produces an output voltage that is typically hundreds of thousands difference between its input terminals. Operational amplifiers

ilding blocks for a wide range of electronic circuits. They had their origins where they were used in many linear, non-linear and frequency

uits. Their popularity in circuit design largely stems from the fact the characteristics of the final elements (such as their gain) are set by external components with little dependence on temperature changes and manufacturing variations in the op

amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. Many standard IC op-amps cost only a few

uction volume; however some integrated or hybrid operational amplifiers with special performance specifications may cost over $100 US in small

amps may be packaged as components, or used as elements of more complex amp is one type of differential amplifier. Other types of

differential amplifier include the fully differential amplifier (similar to the opinstrumentation amplifier (usually built from three op-amps), the

(similar to the instrumentation amplifier, but with tolerance to commonvoltages that would destroy an ordinary op-amp), and negative feedback amplifier

amps and a resistive feedback network).

The amplifier's differential inputs consist of a input and aamp amplifies only the difference in voltage between the two, which is called

. The output voltage of the op-amp is given by the equation,

is the voltage at the non-inverting terminal, is the voltage at the inverting loop gain of the amplifier. (The term "open-loop" refers to the

op from the output to the input). The magnitude offor integrated circuit op-amps—and therefore even a quite small

drives the amplifier output nearly to the supply voltage. This of the amplifier. The magnitude of AOL is not well controlled by the

manufacturing process, and so it is impractical to use an operational amplifier as a stand. If predictable operation is desired, negative feedback

applying a portion of the output voltage to the inverting input. The closed loopgreatly reduces the gain of the amplifier. If negative feedback is used, the circuit's overall gain and other parameters become determined more by the feedback network than by the opamp itself. If the feedback network is made of components with relatively constant, stable values, the unpredictability and inconstancy of the op-amp's parameters do not seriously

amp") is a DC-with a differential input and, usually, a single-

amp produces an output voltage that is typically hundreds of thousands Operational amplifiers

ilding blocks for a wide range of electronic circuits. They had their origins linear and frequency-

uits. Their popularity in circuit design largely stems from the fact the ) are set by external components with

and manufacturing variations in the op-amp itself. amps are among the most widely used electronic devices today, being used in a vast array

amps cost only a few uction volume; however some integrated or hybrid operational

amplifiers with special performance specifications may cost over $100 US in small amps may be packaged as components, or used as elements of more complex

. Other types of (similar to the op-amp, but with

amps), the isolation (similar to the instrumentation amplifier, but with tolerance to common-mode

negative feedback amplifier (usually

input and a input, and two, which is called

amp is given by the equation,

is the voltage at the inverting loop" refers to the

The magnitude of AOL is typically and therefore even a quite small

drives the amplifier output nearly to the supply voltage. This is not well controlled by the

manufacturing process, and so it is impractical to use an operational amplifier as a stand-negative feedback is used, by

closed loop feedback is used, the circuit's overall

gain and other parameters become determined more by the feedback network than by the op-amp itself. If the feedback network is made of components with relatively constant, stable

amp's parameters do not seriously

affect the circuit's performance.switch or comparator. Positive feedback may be used to introduce

1.4.2Ideal and Real Op-Amps

An ideal op-amp is usually considered to have the following properties, and they are considered to hold for all input voltages:

§ Infinite open-loop gain (when doing theoretical analysis, aloop gain AOL goes to infinity).

§ Infinite voltage range available at the output (

the output are limited by the supply voltagesare called rails.

§ Infinite bandwidth (i.e., the frequency magnitude response is considered to be flat everywhere with zero phase shift

§ Infinite input impedance (so, in the diagram, to ).

§ Zero input current (i.e., there is assumed to be no§ Zero input offset voltage (i.e., when the input terminals are shorted so that

output is a virtual ground or§ Infinite slew rate (i.e., the rate

bandwidth (full output voltage and current available at all frequencies).§ Zero output impedance (i.e.,

current). § Zero noise. § Infinite Common-mode rejection ratio§ Infinite Power supply rejection ratio

These ideals can be summarized by the two "golden rules":

I. The output attempts to do whatever is necessary to make the voltage between the inputs zero.II. The inputs draw no current.

affect the circuit's performance. If no negative feedback is used, the op-amp functions as a Positive feedback may be used to introduce hysteresis

Amps:

amp is usually considered to have the following properties, and they are considered to hold for all input voltages:

(when doing theoretical analysis, a limit may be taken as open goes to infinity).

Infinite voltage range available at the output (vout) (in practice the voltages available from

the output are limited by the supply voltages and ). The power supply sources

(i.e., the frequency magnitude response is considered to be flat phase shift).

(so, in the diagram, , and zero current flows from

Zero input current (i.e., there is assumed to be no leakage or bias current into the device).(i.e., when the input terminals are shorted so thator vout = 0).

(i.e., the rate of change of the output voltage is unbounded) and power bandwidth (full output voltage and current available at all frequencies).

(i.e., Rout = 0, so that output voltage does not vary with output

mode rejection ratio (CMRR). Power supply rejection ratio for both power supply rails.

These ideals can be summarized by the two "golden rules":

I. The output attempts to do whatever is necessary to make the voltage between the inputs zero. II. The inputs draw no current.

amp functions as a hysteresis or oscillation.

amp is usually considered to have the following properties, and they are

may be taken as open

practice the voltages available from

). The power supply sources

(i.e., the frequency magnitude response is considered to be flat

, and zero current flows from

current into the device). (i.e., when the input terminals are shorted so that , the

of change of the output voltage is unbounded) and power bandwidth (full output voltage and current available at all frequencies).

not vary with output

I. The output attempts to do whatever is necessary to make the voltage difference

The first rule only applies in the usual case where the op-amp is used in a closed-loop design (negative feedback, where there is a signal path of some sort feeding back from the output to the inverting input). These rules are commonly used as a good first approximation for analyzing or designing op-amp circuits.

In practice, none of these ideals can be perfectly realized, and various shortcomings and compromises have to be accepted. Depending on the parameters of interest, a real op-amp may be modeled to take account of some of the non-infinite or non-zero parameters using equivalent resistors and capacitors in the op-amp model. The designer can then include the effects of these undesirable, but real, effects into the overall performance of the final circuit. Some parameters may turn out to have negligible effect on the final design while others represent actual limitations of the final performance, that must be evaluated.

Op-amps may be classified by their construction:

§ discrete (built from individual transistors or tubes/valves) § IC (fabricated in an Integrated circuit) - most common § hybrid

An integrated circuit or monolithic integrated circuit (also referred to as IC, chip and microchip) is an electronic circuit manufactured by diffusion of trace elements into the surface of a thin substrate of semiconductor material.

Integrated circuits are used in almost all electronic equipment in use today and have revolutionized the world of electronics. Computers, cellular phones and other digital appliances are now inextricable parts of the structure of modern societies, made possible by the low cost of production of integrated circuits.

We also use one such IC LM324 for amplification of the pH sensor signal. LM324 is a Low Power Quad Operational Amplifier.

1.5 DAQ (DATA ACQUISITION):

Data acquisition is the process of sampling signals that measure real world physical

conditions and converting the resulting samples into digital numeric values that can be

manipulated by a computer. Data acquisition systems (abbreviated with the

acronym DAS or DAQ) typically convert analog waveforms into digital values for

processing. The components of data acquisition systems include:

§ Sensors that convert physical parameters to electrical signals.

§ Signal conditioning circuitry to convert sensor signals into a form that can be converted to digital values.

§ Analog-to-digital converters, which convert conditioned sensor signals to digital values.

Data acquisition applications are controlled by software programs developed using various

general purpose programming languages such as C, Fortran, Java, Lisp, Pascal.COMEDI is

an open source API (application program Interface) used by applications to access and

control the data acquisition hardware. Using COMEDI allows the same programs to run on

different operating systems, like Linux and Windows.

Specialized software tools used for building large-scale data acquisition systems

include EPICS. Graphical programming environments include ladder logic, Visual

C++, Visual Basic,MATLAB and LabVIEW.

1.5.1 Source

Data acquisition begins with the physical phenomenon or physical property to be measured.

Examples of this include temperature, light intensity, gas pressure, fluid flow, and force.

Regardless of the type of physical property to be measured, the physical state that is to be

measured must first be transformed into a unified form that can be sampled by a data

acquisition system. The task of performing such transformations falls on devices

called sensors.

A sensor, which is a type of transducer, is a device that converts a physical property into a

corresponding electrical signal (e.g., a voltage or current) or, in many cases, into a

corresponding electrical characteristic (e.g., resistance or capacitance) that can easily be

converted to electrical signal.

The ability of a data acquisition system to measure differing properties depends on having

sensors that are suited to detect the various properties to be measured. There are specific

sensors for many different applications. DAQ systems also employ various signal

conditioning techniques to adequately modify various different electrical signals into voltage

that can then be digitized using an Analog-to-digital converter (ADC).

1.5.2 Signals

Signals may be digital (also called logic signals sometimes) or analog depending on the

transducer used.

Signal conditioning may be necessary if the signal from the transducer is not suitable for the

DAQ hardware being used. The signal may need to be amplified, filtered or demodulated.

Various other examples of signal conditioning might be bridge completion, providing current

or voltage excitation to the sensor, isolation, linearization. For transmission purposes, single

ended analog signals, which are more susceptible to noise can be converted to differential

signals. Once digitized, the signal can be encoded to reduce and correct transmission errors.

1.5.3 DAQ Hardware

DAQ hardware is what usually interfaces between the signal and a PC. It could be in the form

of modules that can be connected to the computer's ports (parallel, serial, USB, etc.) or cards

connected to slots (S-100 bus, AppleBus, ISA, MCA, PCI, PCI-E, etc.) in the mother board.

Usually the space on the back of a PCI card is too small for all the connections needed, so an

external breakout box is required. The cable between this box and the PC can be expensive

due to the many wires, and the required shielding.

DAQ cards often contain multiple components (multiplexer, ADC, DAC, TTL-IO, high

speed timers, RAM). These are accessible via a bus by a microcontroller, which can run small

programs. A controller is more flexible than a hard wired logic, yet cheaper than a CPU so

that it is permissible to block it with simple polling loops. For example: Waiting for a trigger,

starting the ADC, looking up the time, waiting for the ADC to finish, move value to RAM,

switch multiplexer, get TTL input, let DAC proceed with voltage ramp. Many times

reconfigurable logic is used to achieve high speed for specific tasks and digital signal

processors are used after the data has been acquired to obtain some results. The fixed

connection with the PC allows for comfortable compilation and debugging. Using an external

housing a modular design with slots in a bus can grow with the needs of the user.

Not all DAQ hardware has to run permanently connected to a PC, for example intelligent

stand-alone loggers and oscilloscopes, which can be operated from a PC, yet they can operate

completely independent of the PC.

1.5.4 DAQ Software

DAQ software is needed in order for the DAQ hardware to work with a PC. The device driver

performs low-level register writes and reads on the hardware, while exposing a standard API

for developing user applications. A standard API such as C

applications to run on different operating systems, e.g. a user application that runs on

Windows will also run on Linux and BSD.

DAQ software is needed in order for the DAQ hardware to work with a PC. The device driver

level register writes and reads on the hardware, while exposing a standard API

for developing user applications. A standard API such as COMEDI allows the same user

applications to run on different operating systems, e.g. a user application that runs on

Windows will also run on Linux and BSD.

DAQ software is needed in order for the DAQ hardware to work with a PC. The device driver

level register writes and reads on the hardware, while exposing a standard API

OMEDI allows the same user

applications to run on different operating systems, e.g. a user application that runs on

CHAPTER 2

BLOCK DIAGRAM

CIRCUIT DIAGRAM

This circuit is constructed using the virtual circuit simulation software multisim v 10.0.

CHAPTER 3

CIRCUIT DIAGRAM

This circuit is constructed using the virtual circuit simulation software multisim v 10.0.

This circuit is constructed using the virtual circuit simulation software multisim v 10.0.

SYSTEM SIMULATION RESULTS

By taking into account the outputs produced by the pH sensor the circuit is virtually excited using the software multisim v 10.0. By taking those values as consideration the outputs are evaluated. The tally of these results with the practical design and hardware gives the accuracy percentage of the system used.

pH value of the

solution 1 2 3 4 5 6 7 8 9

10 11 12 13 14

CHAPTER 4

SYSTEM SIMULATION RESULTS

By taking into account the outputs produced by the pH sensor the circuit is virtually excited v 10.0. By taking those values as consideration the outputs are

evaluated. The tally of these results with the practical design and hardware gives the accuracy percentage of the system used.

INPUTS(sensors output)

OUTPUTS(giDAQ)

59mV 0.56V 118mV 1.113V177mV 1.664V236mV 2.241V295mV 2.76V 354mV 3.315V413mV 3.866V472mV 4.416V531mV 4.967V590mV 5.571V649mV 6.067V708mV 6.618V767mV 7.167V826mV 7.761V

SYSTEM SIMULATION RESULTS

By taking into account the outputs produced by the pH sensor the circuit is virtually excited v 10.0. By taking those values as consideration the outputs are

evaluated. The tally of these results with the practical design and hardware gives the accuracy

OUTPUTS(given to

1.113V 1.664V 2.241V

3.315V 3.866V 4.416V 4.967V 5.571V 6.067V 6.618V 7.167V 7.761V

The change of the voltage at the output terminal i.e. 1 changes with the gain of the amplifier. The gain of the amplifier is varied by varying the voltage given to the terminals Vcc+ i.e. pin 4 and GND pin 11.

change of the voltage at the output terminal i.e. 1 changes with the gain of the amplifier. The gain of the amplifier is varied by varying the voltage given to the terminals Vcc+ i.e.

change of the voltage at the output terminal i.e. 1 changes with the gain of the amplifier. The gain of the amplifier is varied by varying the voltage given to the terminals Vcc+ i.e.

CHAPTER 5

HARDWARE DESCRIPTION

The components are connected on a Printed

Circuit Board in the non inverting mode to the operational amplifier as shown in the circuit

diagram. The functioning of the non inverting amplifier is simple. The basic circuit for the

non-inverting operational amplifier is relatively straightforward. In this circuit the signal is

applied to the non-inverting input of the op-amp. However the feedback is taken from the

output of the op-amp via a resistor to the inverting input of the operational amplifier where

another resistor is taken to ground. It is the value of these two resistors that govern the gain of

the operational amplifier circuit. The amplification of the circuit is explained mathematically

as

So according to the circuit every input voltage that is given to the circuit is multiplied by

The supply to the op amp is taken from a 12V, 1.5A DC adapter. The

working of the circuit can be explained by the sequence of changes that occur to the

components of the circuit. Initially the pH probe is dipped in to the solution and the output

terminal of it is connected to the input terminal 3 of the IC LM324 which gets excited when

the supply is given to the terminal 4 and terminal 11 of it. Once the IC is energized it

multipies the input voltage as per the given feedback and grounding resistance of it as per the

equation stated above. The pH sensor and the amplifier circuit gets connected and the mV

generated by the pH sensor is taken by the IC and the output is read at terminal 1 of the IC.

This is given as input to the DAQ card that is used, the range of control of pH that has

transformed itself into volts is set by programming the DAQ by setting the limits using the

software LABVIEW. The output of the DAQ card is connected to the motors that drive the

acid container and base container. Once the output of the amplifier circuit is beyond the

voltage limit (which indeed is the pH limit) in either way the corresponding motor will start

running. Say if the pH limits set are 3.5 V and 5 V i.e. from 6 pH to 9 pH, then if the

amplifier output voltage exceeds 5

so the acid motor is given supply and the pH value gets reduced. The opposite happens if the

voltage generated by the amplifier is less than 3.5 V. Thus the control of pH of the solution is

automated whenever it misses its range of control. The hardware designed even as it looks

simple does an important job of controlling the pH of a solution.

5.1. HARDWARE CIRCUIT

The hardware designed can be seen in the figure below.

amplifier output voltage exceeds 5 V then the solution is more basic in nature than required

so the acid motor is given supply and the pH value gets reduced. The opposite happens if the

voltage generated by the amplifier is less than 3.5 V. Thus the control of pH of the solution is

ed whenever it misses its range of control. The hardware designed even as it looks

simple does an important job of controlling the pH of a solution.

. HARDWARE CIRCUIT:

The hardware designed can be seen in the figure below.

V then the solution is more basic in nature than required

so the acid motor is given supply and the pH value gets reduced. The opposite happens if the

voltage generated by the amplifier is less than 3.5 V. Thus the control of pH of the solution is

ed whenever it misses its range of control. The hardware designed even as it looks

CHAPTER 6

SOFTWARE DESCRIPTIONS

The softwares used for the circuit eventually help the user the validity and control of the

circuit. The softwares used for the project are

• MULTISIM

• LABVIEW

6.1. MULTISIM:

Multisim is one such software that helps the user For dete • Generate mathematical models of electronic components. • Test performance without actually building the circuit . • Calculating parameters of non-linear devices. • To test the validity of the circuit. Most of the components that are available in the electronic market today are available in the updating versions of multisim. These updated versions consists almost all the components that came into existence into the market after its previous version. Using this software in testing of circuits help us from the burden of practical building up of circuits.

6.1.2 Use of Multisim in the Project:

Many circuits where constructed using this software that can give precise result for the pH sensor that is used in the project. The components were chosen such that the IC used can sense a change in the input and can produce the output such that it s DAQ compatible. The following circuit can best explain the purpose of the software in this project.

Calculating parameters of non-linear devices

The maximum permissible voltage that a DAQ can take is 10V s

maximum voltage that is to be given to the circuit to 8V.

The maximum permissible voltage that a DAQ can take is 10V so the circuit limits the

maximum voltage that is to be given to the circuit to 8V.

o the circuit limits the

The minimum change in the voltage that a DAQ can sense is 135mV the initial output that

the amplifier circuit gives is almost thrice the minimum sensible voltage.

The purpose of the software in the project played a major role in deciding the components

that are to be used for the project.

6.2. LabVIEW:

LabVIEW is the software that is used for graphical programming of a system. LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for avisual programming language from National Instruments. The purpose of such programming is automating the usage of processing and measuring equipment in any laboratory setup.

LabVIEW ties the creation of user interfaces (called front panels) into the development cycle. LabVIEW programs/subroutines are called virtual instruments (VIs). Each VI has three components: a block diagram, a front panel and a connector panel. The last is used to represent the VI in the block diagrams of other, calling VIs. Controls and indicators on the front panel allow an operator to input data into or extract data from a running virtual instrument. However, the front panel can also serve as a programmatic interface. Thus a virtual instrument can either be run as a program, with the front panel serving as a user interface, or, when dropped as a node onto the block diagram, the front panel defines the inputs and outputs for the given node through the connector pane. This implies each VI can be easily tested before being embedded as a subroutine into a larger program.

The graphical approach also allows non-programmers to build programs by dragging and dropping virtual representations of lab equipment with which they are already familiar. The LabVIEW programming environment, with the included examples and the documentation, makes it simple to create small applications. This is a benefit on one side, but there is also a certain danger of underestimating the expertise needed for good quality "G" programming. For complex algorithms or large-scale code, it is important that the programmer possess an extensive knowledge of the special LabVIEW syntax and the topology of its memory management. The most advanced LabVIEW development systems offer the possibility of building stand-alone applications. Furthermore, it is possible to create distributed applications, which communicate by a client/server scheme, and are therefore easier to implement due to the inherently parallel nature of G-code.

The other benefits of LabVIEW are stated below

• Interfacing

• Code compilation

• Recoding

• Code re-use

6.2.1 Use of LabVIEW in the Project:

The use of LabVIEW in this project is explained below:

As we see from the figure above the output that is produced by the amplifier circuit is

given to the DAQ which is represented as DAQ assistant. This output is given to an adder

that increases the value as for the voltage can represent the pH on the compute

voltage is given to two controllers which set limits the outputs that are produced by the

controller if exceed the limit the corresponding LED glows.

6.2.2 Interfacing With DAQ

The sequence of programming a DAQ is well unders

steps.

a) First the output of the circuit is to be connected to the analog terminals of

the DAQ as per the terminology given on DAQ.

b) Connect the DAQ to the PC with the USB connector given. See if the light of the

DAQ is blinking.

n the Project:

The use of LabVIEW in this project is explained below:

As we see from the figure above the output that is produced by the amplifier circuit is

given to the DAQ which is represented as DAQ assistant. This output is given to an adder

that increases the value as for the voltage can represent the pH on the compute

voltage is given to two controllers which set limits the outputs that are produced by the

controller if exceed the limit the corresponding LED glows.

With DAQ:

The sequence of programming a DAQ is well understood if explained in

First the output of the circuit is to be connected to the analog terminals of

the DAQ as per the terminology given on DAQ.

Connect the DAQ to the PC with the USB connector given. See if the light of the

As we see from the figure above the output that is produced by the amplifier circuit is

given to the DAQ which is represented as DAQ assistant. This output is given to an adder

that increases the value as for the voltage can represent the pH on the computer. This

voltage is given to two controllers which set limits the outputs that are produced by the

tood if explained in

First the output of the circuit is to be connected to the analog terminals of

Connect the DAQ to the PC with the USB connector given. See if the light of the

c) Open the LabVIEW software and go to the subroutine called DAQ that is to be

installed before starting of the project.

d) Follow the user interface window that gets displayed. This is highly user friendly.

e) We need to receive the output which is in the form of voltage so click on the

corresponding icon buttons displayed.

f) Now the DAQ terminals are displayed and the terminal to which the input is given

is to be selected.

g) Now drop in the component “DAQ assistant” from where the voltages generated

by the amplifier circuit can be viewed.

h) Further the output that is obtained from the “DAQ assistant” can be programmed

graphically as per the requirement.

OUTPUTS OBSERVED

CHAPTER 7

OUTPUTS OBSERVED

Practical voltage outputs are noted after interfacing the DAQ with the circuit

pH of the

solution

pH sensor

output

1 59mV

2 118mV

3 177mV

4 236mV

5 295mV

6 354mV

7 413mV

8 472mV

9 531mV

10 590mV

11 649mV

12 708mV

13 767mV

14 826mV

Practical voltage outputs are noted after interfacing the DAQ with the circuit

pH sensor

output

Amplifier

output

Acid motor

LED

59mV 539mV OFF

118mV 1.065V OFF

177mV 1.61V OFF

236mV 2.15V OFF

295mV 2.59V OFF

354mV 3.13V OFF

413mV 3.65V OFF

472mV 4.25V ON

531mV 4.70V ON

590mV 5.92V ON

649mV 5.89V ON

708mV 6.42V ON

767mV 6.98V ON

826mV 7.64V ON

Practical voltage outputs are noted after interfacing the DAQ with the circuit

Base motor

LED

ON

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

CHAPTER 8

CONCLUSION AND SCOPE FOR FUTURE WORK

8.1 CONCLUSION:

The input voltage to the amplifier circuit is given from a pH sensor that

generated a voltage in the order of mV for the change in pH that occurs in the solution.

This voltage is amplified by the amplifier circuit to range where the output of the

amplifier circuit is adaptable by the DAQ card that is being used.

The requirements of the range of control of pH is to be observed and

the programming in the labview is to be executed by keeping in to view the circuit output

production chart.

The pH value can be easily controlled between varied ranges of values

just by changing the limits used in the software to program the DAQ. This project is practical

and highly feasible in economic point of view, and has an advantage of controlling the pH

value in a wide range. This project is an automated, reliable and adaptable way of controlling

the pH value in a bioreactor.

8.2 SCOPE FOR FUTURE DEVELOPMENTS:

This pH control can be adapted in industries where

the cleaning and drying of machine parts in the acids exist. Further for making this adaptive

for factories the control part of the project can be made cheaper by using a pair of

comparators that set the limits of control instead of using a DAQ. This amendment in the

circuit will minimize the cost of pH control and efficiency of the circuit also remains

satisfactory.

REFERENCES

BOOKS:

• Op Amp Applications Handbook, Analog Devices, Inc., edited by Walt Jorg.

• LabVIEW™ for Data Acquisition,By: Bruce Mihura, Publisher: Prentice Hall

• pH Sensors and Meters for Laboratory and Process Applications, By John Turner

WEBSITES:

• http://www.sensorland.com/HowPage037.html

• http://en.wikipedia.org/wiki/Data_acquisition

• http://www.national.com/mpf/LM/LM324.html#Overview

• http://www.alldatasheet.com/

• http://www.electronics-tutorials.ws/opamp/opamp_3.html

APPENDIX – A

LIST OF COMPONENTS

Type of the component Name of the component No.of components

Integrated Circuit LM324 1

Resistors 12KΩ, 100KΩ 1

Adapter 230VAC to 12V, 1.5A

DC

1

DAQ 6009 1

pH sensor DpH500 1

Programming software

with a compatible

computer

LabVIEW v 7.0.2 1

APPENDIX – B

DATASHEET OF DAQ 6009

NI USB-6009

14-Bit, 48 kS/s Low-Cost Multifunction DAQ

• 8 analog inputs (14-bit, 48 kS/s)

• 2 analog outputs (12-bit, 150 S/s); 12 digital I/O; 32-bit counter

• Bus-powered for high mobility; built-in signal connectivity

• OEM version available

• Compatible with LabVIEW, LabWindows/CVI, and Measurement Studio for Visual Studio .NET

• NI-DAQmx driver software and NI LabVIEW SignalExpress LE interactive data-logging software

Overview

The National Instruments USB-6009 provides basic data acquisition functionality for applications such as simple data logging, portable measurements, and academic lab experiments. It is affordable for student use and powerful enough for more sophisticated measurement applications. For Mac OS X and Linux users, download the NI-DAQmx Base driver software and program the USB-6009 with LabVIEW or C.

To supplement simulation, measurement, and automation theory courses with practical experiments, NI developed a USB-6009 Student Kit that includes a copy of the LabVIEW Student Edition. These kits are exclusively for students, giving them a powerful, low-cost, hands-on learning tool. Visit the NI academic products page at http://www.ni.com/academic/measurements.htm for more details.

For faster sampling, more accurate measurements, and higher channel count, consider the NI USB-6210 and NI USB-6211 high-performance USB data acquisition devices.

Every NI USB data acquisition device includes a copy of NI LabVIEW SignalExpress LE so you can quickly acquire, analyze, and present data without programming. In addition to LabVIEW SignalExpress, USB data acquisition modules are compatible with the following versions (or later) of NI application software – LabVIEW 7.x, LabWindows™/CVI 7.x, or Measurement Studio 7.x. USB data acquisition modules are also compatible with Visual Studio .NET, C/C++, and Visual Basic 6.

Specifications

Specifications Documents • Specifications (3) • Data Sheet

Specifications Summary

General

Product Name USB-6009

Product Family Multifunction Data Acquisition

Form Factor USB

Part Number 779026-01

Operating System/Target Windows , Linux , Mac OS , Pocket PC

DAQ Product Family B Series

Measurement Type Voltage

RoHS Compliant Yes

Analog Input

Channels 8 , 4

Single-Ended Channels 8

Differential Channels 4

Resolution 14 bits

Sample Rate 48 kS/s

Throughput 48 kS/s

Max Voltage 10 V

Maximum Voltage Range -10 V , 10 V

Maximum Voltage Range Accuracy 138 mV

Minimum Voltage Range -1 V , 1 V

Minimum Voltage Range Accuracy 37.5 mV

Number of Ranges 8

Simultaneous Sampling No

On-Board Memory 512 B

Analog Output

Channels 2

Resolution 12 bits

Max Voltage 5 V

Maximum Voltage Range 0 V , 5 V

Maximum Voltage Range Accuracy 7 mV

Minimum Voltage Range 0 V , 5 V

Minimum Voltage Range Accuracy 7 mV

Update Rate 150 S/s

Current Drive Single 5 mA

Current Drive All 10 mA

Digital I/O

Bidirectional Channels 12

Input-Only Channels 0

Output-Only Channels 0

Number of Channels 12 , 0 , 0

Timing Software

Logic Levels TTL

Input Current Flow Sinking , Sourcing

Output Current Flow Sinking , Sourcing

Programmable Input Filters No

Supports Programmable Power-Up States? No

Current Drive Single 8.5 mA

Current Drive All 102 mA

Watchdog Timer No

Supports Handshaking I/O? No

Supports Pattern I/O? No

Maximum Input Range 0 V , 5 V

Maximum Output Range 0 V , 5 V

Counter/Timers

Counters 1

Buffered Operations No

Debouncing/Glitch Removal No

GPS Synchronization No

Maximum Range 0 V , 5 V

Max Source Frequency 5 MHz

Minimum Input Pulse Width 100 ns

Pulse Generation No

Resolution 32 bits

Timebase Stability 50 ppm

Logic Levels TTL

Physical Specifications

Length 8.51 cm

Width 8.18 cm

Height 2.31 cm

I/O Connector Screw terminals

Timing/Triggering/Synchronization

Triggering Digital

Synchronization Bus (RTSI) No

Pricing

Are you looking for order or quoting information? Select the country where you will use the product so that we can provide accurate pricing, availability and purchasing information.

NI USB-6009 Complete Package Each NI USB-6009 requires:

NI USB-6009 Software

Roll over icons above to learn why you need each item in the package.

NI USB-6009 and Accessories Select Your Country

NI USB-6009 - 779026-01 For price, Select Your Country

Optional Accessories Hide

USB 6008/09 Accessory Kit - 779371-01

For price, Select Your Country

USB 6000 Series Prototyping Accessory - 779511-01

For price, Select Your Country

Software Select Your Country Note : You should only purchase this device without software if you already own compatible application software.

NI LabVIEW SignalExpress - 779037-35 For price, Select Your Country

You need software to interface with your hardware and to collect, analyze, present, and store your measurements. This board is compatible with a variety of programming languages, including LabVIEW, C/C++, Visual Basic, and .NET. LabVIEW provides the easiest integration with all of your NI hardware and is recommended to maximize your hardware investment. Please select the country where you will use the product(s) so that we can provide you with accurate pricing, availability, and purchasing information

Services

Extended Warranties

National Instruments designs and manufactures all products to minimize failures, however unexpected failures can still occur. Extended warranties provide a fixed economical price at the time of system purchase, covering any repair costs for up to three years. In addition, they offer the following benefits: • Significant cost savings compared to individual repair incidents • Fault location, diagnostics, and repair by NI any time the system product fails • All parts and labor costs covered as well as any adjustments needed to restore the hardware to manufacturing specifications For more information about your warranty options: • Learn More About Warranty Services [http://www.ni.com/services/warranty.htm] • Talk to an Expert About Extended Warranties [javascript:openCallMeWindowCTA(document.referrer,%20’US’)] • View Warranty Repair Policies [http://www.ni.com/services/warranty_repair_policies.htm]

Calibration

NI recognizes the need to maintain properly calibrated devices for high-accuracy measurements. NI provides manual calibration procedures, services to recalibrate your products, and automated calibration software to calibrate many NI measurement products. • Learn More About Calibration Services [http://www.ni.com/services/calibration.htm]

Training

NI training is the fastest, most certain route to productivity with NI tools and successful application development. • Learn More About NI Training and Certification [http://www.ni.com/training/] • Find a Course Near You and View Schedules [http://sine.ni.com/apps/utf8/nisv.custed]

Repair Services

Return your registered product under warranty at no additional labor and parts cost. NI offers fault location, diagnostics, and repair any time the system fails as well as any adjustments needed to restore the hardware to manufacturing specifications. • Learn More About Repair Services [http://www.ni.com/services/warranty.htm] • Contact NI to obtain a Return Material Authorization (RMA) form and shipping instructions.

[http://sine.ni.com/apps/utf8/nicc.call_me] • View your RMA support request status online. [http://www.ni.com/support/servicereq/] • Register your product [http://www.ni.com/register] .

Technical Support

ni.com/support [http://www.ni.com/support/]

Resources

Additional Product Information • Manuals (4) • Dimensional Drawings (2) • Product Certifications

Related Information • NI USB Data Acquisition for OEM • Download NI Data Acquisition Drivers • NI LabVIEW SignalExpress Interactive Data-Logging Software

APPENDIX – C

DATASHEET OF IC LM324