This document discusses data acquisition (DAQ) systems. It begins with an introduction to DAQ and defines it as the process of measuring physical phenomena like voltage, current, temperature etc. and converting it to digital form. It then presents a block diagram of typical DAQ components like transducers, signal conditioning, A/D conversion, telemetry etc. and discusses each component in detail. It explains the working of DAQ systems from data collection through sensors to digital conversion and software processing. Finally, it outlines the advantages and applications of DAQ systems in various industries like aerospace, medicine, manufacturing etc.

1. BY-Akash Kumar
Atul
Roll No.-1922019

2. TOPICS TO BE DISCUSSED
1. Introduction to DAQ systems.
2. Block Diagram.
3. Working principal.
4. Advantages of DAQ systems
5. Disadvantages of DAQ sysrems
6. Applications

3. INTRODUCTION
• Data acquisition (DAQ) is the process of collecting and
measuring an electrical or physical phenomenon such as
voltage, current, temperature, pressure, or sound with a
computer.
• DAQ systems capture, measure, and analyze physical
phenomena from the real world.
• Data acquisition systems (abbreviated with the
acronym DAS or DAQ) typically convert analog waveforms into
digital values for easy processing.

4. BLOCK DIAGRAM FOR DAQ
Physical
Variables
Transducer
Signal
Conditioning
Telemetry
Signal
Recovery
Data
Processing
Recording &
Display

5. PHYSICAL VARIABLE
• Physical condition that can be used as input of DAS or which
can be represented in Digital form.
Physical Variables Sensors
Acceleration Accelerometer
Sound Microphone
Pressure Pressure gauge
Temperature Thermocouple
Force Strain gauge
Light Photoconductive cell

6. TRANSDUCERS
• A transducer is an electrical device which is used to convert one
form of energy into another form.
• In general, these devices deal with different types of energies
such as mechanical, electrical energy, light energy, chemical
energy, thermal energy, acoustic energy, electromagnetic
energy, and so on.
• A transducer thus converts the physical conditions in electrical
waveform for easy signal processing.

7. SIGNAL CONDITIONING
• To measure signals from transducers, you must convert them
into a form a Signal Conditioning measurement device can
accept.
• It can be defined as an excitation and amplification system for
various transducers.
• Common types of signal conditioning include amplification,
linearization, transducer excitation, and isolation.

8. DIFFERENT TYPE OF SIGNAL CONDITIONING
• Amplification- It is one of the most common signal conditioning functions.
Amplification expands the range of the transducer signals so that they match the
input range of the A/D converter.
• Isolation- Isolation blocks high-voltage surges and rejects high common-mode
voltage and thus protects both the operators and expensive measurement
equipment. Isolated signal conditioning devices pass the signal from its source to
the measurement device .
• Filtering- Filters reject unwanted noise within a certain frequency range. Another
common use for filtering is to prevent aliasing from high-frequency signals.
• Linearization- Linearization is the process of interpreting the signal from the sensor
and can be done either with signal conditioning or through software. It is necessary
when sensors produce voltage signals that are not linearly related to the physical
measurement.

9. SAMPLE AND HOLD CIRCUIT
• The Sample and Hold circuit is an electronic circuit which creates
the samples of voltage when input given, and it holds these
samples for the definite time.
• After Signal conditioning DAQ receives many analog signal from
it which is needed to be converted into constant voltage over
gating period by means of S/H circuit.
• When the pulse is high, signal is sampled and when low, signal
value is hold.

10. CIRCUIT DIAGRAM FOR S/H CIRCUIT
Analog I/P
Control Signal
Hold Capacitor
Analog O/P
Switch
Ground

11. A/D CONVERTER
• An A/D converter is a device that converts analog signals
(usually voltage) obtained from environmental (physical)
phenomena into digital format.
• Conversion involves a series of steps, including sampling,
quantization, and coding
amp
A/D
Convert
er
0101010101
01
0101001101
0110010010
0100100101
110101
Analog
signal
Digita
l

12. TELEMETRY
• It is used to transmit measured quantity to a remote location
for processing recording and displaying.
• It refers to transmission of any measured variables like
temperature, pressure, and flow.
• We divide telemetry into DC telemetry, AC telemetry, Current
telemetry, Voltage telemetry, Position telemetry, Radio
telemetry and so on.

13. TYPES OF TELEMETRY
• Voltage Telemetry-Voltage telemetry system use primary
sensing element which produces a proportional voltage signal.
Some examples of primary sensing element are-
Thermocouple, Tachometer, LVDT. It must have high
quality circuits than current telemetry system and relatively
high SNR.
• Current Telemetry- Basically it helps in connecting the
transmission line from transmitter end to receiver end. This
type of telemetry employs a torque balance method in which
the current in wire is used to apply a torque to balance a torque

14. SIGNAL RECOVERY
• The signal receiving at receiving end are generally corrupted by
noise.
• When signal to noise ratio is poor, it become necessary to
employ a measurement technique to separate the noise from
the signal. This technique is called Signal Recovery.
• These are the four principle methods used for signal recovery. Signal Filtering
 Signal Averaging
 Signal Correlation
 Signal Coding

15. DATA PROCESSING & DAQ SOFTWARE
• Processing of signal is performed to control purposes or to
modify data before recording or to perform some types of
analysis on the data.
• DAQ software is needed in order for the DAQ hardware to work
with a PC.
• It involves the use of a programming language, such as:
C++, visual C++, Pascal, Ladder logic, Lab view

16. HOW IT WORKS
Regardless of what the system is converting, all data acquisition systems
follow the same basic procedure.
1. DAQ begins with collection of data of physical variables through
sensors.
2. After gathering the data, the sensors will output it on to signal
conditioning circuitry, which converts the data into an analog input.
3. From there, A/D converters convert the analog signal data into a singular
digital form.
4. Once the data has been converted into a singular form, the system
inputs it into the software. From there, it can be accessed and controlled
by data acquisition software programs that use a variety of programming
languages, such as Pascal, BASIC, C++, LabVIEW, and Java.

17. ADVANTAGE OF DAQ
• DAQ systems are simple, powerful, and flexible which can be
used with a wide range of applications.
• DAQ can be used to increase productivity with lower costs.
• Improved data security.
• Data can be interpreted with high level of accuracy.
• Reduced data redundancy, updating errors and increased
consistency.

18. DISADVANTAGE OF DAQ
• Database systems are complex, difficult, and time-consuming
to design.
• Initial training required for all programmers and users.
• Extensive conversion costs in moving from a file based system
to a database system.
• Damage to database affects virtually all applications programs.

19. APPLICATIONS OF DAQ
• DAQ technology is used in many industries which include
aerospace, medicine, wastewater services, and industrial
manufacturing.
• Some of more common use of DAQ systems include testing of
all kind of applications such as field studies, troubleshooting
and research.
• Along with monitoring and adjustments of the processes, it can
be used to test all types of technical products.

20. YOU