This presentation deals with the most important part of LABVIEW which is the Data Acquisition which mainly deals with how the signal is generated and distributed virtually.

1. BY – ABHISHEK SUR
SYSTEM ID- 2019595927
ROLL NO -190134001
SUBMITTED TO – SUMAN LATA DHAR

2.  DATA ACQUISITION
 ROLE OF TRANSDUCERS
 ANALOG SIGNALS
 SIGNAL CONDITIONING
 PARTS OF SIGNAL CONDITIONING
 COMPONENTS OF DAQ DEVICES

3.  Data acquisition involves gathering signals from a
measuring sources and then digitizing the signals
for storage, analysis and presentation on a PC.
 It may come in many different PC technology
forms to offer flexibility while choosing a
system.
 The main components for building a basic DAC
system are:-
 Transducers and Sensors
 Signals
 Signal conditioning
 DAQ hardware
 Driver and Application Software

4.  Now, Transducer is a device that converts a
physical phenomenon into measurable
electrical signal such as voltage or current
 It has the same agreement like that of
sensors in data acquisition system.
 There are specific transducers for many
different applications such as measuring
temparature, pressure and fluid flow.

5.  Phenomenon
 Temperature
 Light
 Sound
 Force &Pressure
 Acceleration
 Transducers
 Thermocouple, RTD
 Photo Sensor
 Microphone
 Strain gauge
 Accelerometer

6.  It is a type of signals that can exist at any
value with respect to time. Examples are
voltage, temperature, pressure, load.
 The three primary characteristics of an
analog signal are level, shape and frequency.

7.  LEVEL:- It gives us the vital information
about the measured analog signal. As when
we measure it the signal doesn't change
quickly with time. The accuracy is also
important.
 SHAPE:- Some signals are named after
specific shapes as square, sawtooth, triangle
etc. It is important because by analyzing the
shape we can further analyse the signal.

8.  FREQUENCY:- All analog signals can be
categorized by their frequencies. Unlike
level or shape you cannot directly measure
frequency. But it can be analysed in a
software through Fourier Transform.

9.  Sometimes transducers generate signals too
difficult to measure with a data acquisition
device.
 For that reason only signal conditioning is
used as for noisy environment, extreme high
or low signals it is used.
 It also maximizes the accuracy of the system
and allows sensor to operate properly and
assures safety.

10.  It is important to select the right hardware
for signal conditioning. It can be both
modular and integrated type:-
 Amplification
 Linearization
 Filtering
 Multiplexing

11.  Improves the accuracy in the digitized signal
and reduces the effects of the noise.
 Signals should be amplified close to the
source results into high SNR.
 For highest accuracy amplify the voltage
level to maximum input range of ADC.

12.  Most of the transducers have non-linear
response.
 LabVIEW can linearize the voltage levels
from transducers so that you can scale the
voltages to the measured phenomenon.
 Software based.

13.  It is to remove unwanted signals from the
signal of interest i.e. the signal which is to
be measured.
 Noise reduces the measurement accuracy.
 For DC signals Many SCXI-
Signal Conditioning Extension for Instrumenta
tion modules uses 4Hz and 10kHz low pass
filters to eliminate the noise before the
signals are digitized by DAQ device.

14.  Technique for measuring several signals with
a single device.
 The ADC samples one channel, switches to
next channel samples it, switches to next
channel and so on.
 Because same ADC samples many channels
instead of one, the effective sampling rate of
the individual channel is inversely to number
of channels sampled.

15.  Analog I/O
 Digital I/O
 MUX
 ADC
 DAC
 Counter
 RTSI (Real Time System Integration) Bus

16.  The DAQ device is an external and connects
to the computer through an exiting port such
as serial port or Ethernet port .
 The computer receives the raw data through
DAQ Device.
 The application which is written in the
software presents and manipulates the raw
data so that it can be understood.
 Software also controls the DAQ system by
commanding the DAQ device and manages
when and from which channel to acquire the
data.