In this slide there is all about the digital transducer and its types.Its is very helpful in making short notes of transducer. There is a simple description.

1. DIGITAL TRANSDUCER

2.  INTRODUCTION
 WORKING PRINCIPAL
 CONSTRUCTION OF DIGITAL TRANSDUCER
 CLASSIFICATION OF DIGITAL TRANSDUCER
 ADVANTAGES & DISADVANTAGES OF DIGITAL TRANSDUCER
 APPLICATION

3. • Any transducer that presents information as discrete samples
and that does not introduce a quantization error when the
reading is represented in the digital form may be classified as
digital transducer..
• What is encoder?
• Any transducer that generates a coded of a measurement can
be termed an encoder.
• Most transducer used in digital system are primarily analogue
in nature and incorporate conversion to provide the digital
output. Many special technique have been developed to avoid
the necessity to use a conventional analogue –to-digital
conversion technique to produce the digital signal.

4.  Some of the techniques used in transducers which are
particularly adaptable for use in digital system are introduced
in following ways-
 Shaft encoder
 Digital resolvers
 Digital Tachometers
 Hall effect sensors
 Limit switches
 The use of encoder disc for absolute and incremental position
measurement and to provide measurement of speed are
outlined. The application of linear grating for measurement of
translational displacement is compared with the use of Moire
fringe techniques. Synchro devices and the various
techniques used to produce a digital output.

5.  CLASSIFICATION OF DIGITAL DISPLACEMENT TRANSDUCER
 They are basically are of two types-absolute and incremental
encoders.
 ABSOLUTE ENCODER-
 An absolute encoder maintain position information when
power is removed from the systems. The position of the
encoder is immediately on applying power.
 The system does not need to return to a calibration point to
maintain position accuracy.
 A high resolution wheels measures the fractional rotation,and
lower resolution geared code wheels records the number of
whole revolution of the shaft.

7.  The problem caused by reverse motion in the case of
tachometer encoder are solved by using incremental encoder.
 The incremental encoder use ( At least two sometimes three)
signal generating elements.
 The two tracks in this case are mechanically shifted by ¼
cycle relative to each other.
 This allow detection of motion which signal rises first .thus,
an up down pulse counter can be used to subtract pulses
whenever the motion reverse.
 A third output which produces one pulse per revolution at a
distinct point,is sometimes provided for zero reference.

9.  door control services
 Robotics
 Drilling machines
 Length measurement
 CNC machines
 Automatic welding
 Radar
 Winding machines
 Wind turbines
 Telescope
 Medical equipment
 Bar code readers

10. Motor speed/rpm
readout
Linear measurement /cut
to length

11. Applicaion of digital
resolvers
BLOCK DIAGRAM
Application
 Position and velocity
sensing
 Medical devices
 CNC machines tools
 Brushless DC servo
commutation.
 Position and velocity
sensing

12.  It is an instrument measuring the rotation speed of a shaft or
a disk, as in motor and other machine.
 The word comes from Greek tachos means “speed” and
metron, means “to measure”.
 Digital tachometers are particulary suitable for precision
measurement and monitoring of all the time related
quantities, which are able to be converted into a proportional
frequency using appropriate sensors time related quantities.
 The instrument can be programmed to measure absolute
value ratio , or proportional difference.

13. application Digital tachometer kit
 Traffic engineering
 In trains and light rails
vehicles
 In analogue audio
recording