digital transducer, uploaded on 2015-11-30.pdf

Digital Transducer

1. DIGITAL TRANSDUCERS
Presented By:
Mohd Kamran Ikram
Mujtaba Hasan
Md. Sharique Ahmad
Akram Najfi
Akshay Sharma

2. CONTENTS
Introduction
Advantages
Types
Shaft Encoders
Digital Resolvers
Digital Tachometers
Hall Effect Sensors
Limit Switches

3. What is a Transducer?
A device that converts variations in a physical quantity,
such as pressure or brightness, into an electrical signal,
or vice versa.

4. The Digital Transducers
Transducers, on the basis of nature of output signal, may
be classified into analog and digital transducers.

Digital transducers convert the input quantity into an
electrical output which is in the form of Pulses.

5. The Block Diagram

6. Advantages
 Ease of generating, manipulating and storing digital signals.

Digital signals can be transmitted over a long distance without
causing much distortion due to amplitude variation and phase shift.

Performs measurement with absolute accuracy and discrimination.

 Gives simplified data presentation.

7. Types
Shaft Encoders
Digital Resolvers
Digital Tachometers
Hall Effect Sensors
Limit Switches

8. Shaft Encoders
 Provide digital output measurements of angular position and
velocity.
Basically of two types- absolute and incremental encoders.
Applicable in robotics, machine tools and mirror positioning
systems etc.

9. Absolute Encoders
Maintains position information when power is removed from
system.
Position of encoder is available immediately on applying
power.
Relationship between encoder value and physical position of
controlled machinery is set at assembly i.e. system doesn’t
need to return to a calibration point for maintaining accuracy.

10. Incremental Encoders
Accurately records changes in position.
Doesn’t power up with a fixed relation between encoder state and
physical position.
System needs to return to a fixed reference point to initialize the
position measurement.

11. Encoder Applications
Door Control Devices
Lens Grinding Machines
Labeling Machines
Drilling Machines
Mixing Machines
Robotics
Length Measurement
Elevators
Bar Code Readers
Conveyors
Radars

12. The Digital Resolvers
Position Sensor Or Transducer

Measures The Angular Position Of Rotating Shaft

Digital Resolvers Use A Rotary Coupling
Transformer

13. Characteristics
Compact

low cost angular position transducers with dc input and
digital output.

Perform efficiently under temperature extremes, humidity,
shock and vibration.

Superior to encoders in terms of ruggedness, size, accuracy
and resolution.

14. Applications
Position And Velocity Sensing

Brushless Dc Servo Commutation

Robotics And Factory Automation

Material Handling

Cnc Machine Tools

15. Digital Tachometers
Digital tachometer is a digital device that
measures and indicates the speed of a rotating
object.
Able to be converted into proportional frequency
using appropriate sensors.
Measures speed of rotating objects, object like-
ceiling fan ,automobile tyres etc.
Tachometer indicates reading in rpm.
There are mainly two types of Digital Tachometer.

16. Types Of Digital Tachometer
Contact Type :

A tachometer which is in contact with the
rotating shaft is known as contact type
tachometer.

This kind of tachometer is generally fixed to
the machine or Electric Motor

Capable of measuring low-speeds at 0.5 rpm
and high speed at 10,000 rpm.

17. Non-Contact Type :

A tachometer that does not need any physical contact with
the rotating shaft is called as noncontact digital
tachometer.
A laser or an optical disk is attached to the rotating
shaft. This type of tachometer can measure from 1 to
99,999 rpm.

18. Applications
Traffic Engineering- for estimating traffic speed and
volume(flow).
In trains and light rail vehicles.
Analogue audio recording- measures speed of audiotape as it
passes across the head.
Medical Instruments.
Laser Instruments.

19. Hall Effect Sensors
A transducer that varies its output voltage in
response to a magnetic field.

Frequently, a hall sensor is combined with circuitry
that allows the device to act in a digital (on/off)
mode.

Commonly used to time the speed of wheels and
shafts, also used in brushless dc electric motors to
detect the position of the permanent magnet and
for current sensing.

20. Limit Switches
It is a switch operated by the motion of a machine part or presence of
an object.

Are used in a variety of applications and environments because of
their ruggedness, ease of installation, and reliability of operation.

They can determine the presence or absence, passing, positioning, and
end of travel of an object.

21. References
https://en.wikipedia.org/

Kalsi H S, Tata McGraw-Hill Education, 2013

http://www.elprocus.com/communication/

https://en.wikipedia.org/

Kalsi H S, Tata McGraw-Hill Education, 2013

http://www.elprocus.com/communication/

22. Thank You…!