For Sensors

1. DEPARTMENT OF MECHANICAL
ENGINEERING
I-SEMESTER
M.TECH-ME-1902
SENSORS APPLICATION IN MANUFACTURING
Dr.Girish M Dhote
DEPARTMENT OF MECHANICAL ENGINEERING
YCCE NAGPUR

2. Outline
 Measurement system
 Sensors and transducers
 Potentiometer sensors
 Principle of operation
 Construction and working
 Applications

3. Measurement systems (MS)
 Collection of information on system status -
 feeding to the micro-processor(s)
 control of the system
 MS = sensors, transducers and signal
processing devices

4. Sensors and transducers
Sensor
Transducer
Physical variable
change,
Temperature
Passive element
change, ΔR, ΔL,
ΔC
Physical variable
change,
Temperature
Active element
change, ΔV,ΔI

5. Sensors and transducers
 A wire of Constantan alloy (copper-nickel
55-45% alloy) - a sensor - variation in
mechanical displacement (tension or
compression) can be sensed as change in
electric resistance.
 This wire + appropriate electrodes and
input-output mechanism attached ->
transducer

6. Sensors and transducers
 Displacement, position and proximity
 Potentiometer
 Strain-gauge element
 Capacitive element
 Differential transformers
 Eddy current proximity sensors
 Inductive proximity switch
 Optical encoders
 Pneumatic sensors
 Proximity switches (magnetic)
 Hall effect sensors

7. Sensors
 Velocity and motion
 Incremental encoder
 Tachogenerator
 Pyroelectric sensors
 Force
 Strain gauge load cell
 Piezo-electric sensors
 Fluid pressure
 Diaphragm pressure gauge
 Capsules, bellows, pressure tubes
 Piezoelectric sensors
 Tactile sensor

8. Sensors
 Liquid flow
 Orifice plate
 Turbine meter
 Liquid level
 Floats
 Differential pressure

9. Sensors
 Temperature
 Bimetallic strips
 Resistance temperature detectors
 Thermistors
 Thermo-diodes and transistors
 Thermocouples
 Light sensors
 Photo diodes
 Photo resistors
 Photo transistor

10. Sensors
 Displacement sensors: measurement of an amount by which
an object has been moved
 Position sensor: determination of position of an object in
relation to some reference point
 Proximity sensors:
 Form of position sensors
 Movement within some particular critical distance of sensor
 Contact and non-contact type

11. Potentiometer Sensors
 Resistance element with
sliding contact
 Linear or rotary
 Linear / Circular wire-
wound track or film of
conductive plastic
 Displacement is
measured based on
potential difference
 Plastic resin
embedded with
carbon powder

13. Applications
Throttle valve
Throttle
Cable-free
acceleration
Adjustment of voltage
Electronic suspension

14. Applications
 control systems with a feedback loop : machine-tool controls
 elevators
 liquid-level assemblies
 forklift trucks
 automobile throttle controls
 control of injection molding machines
 woodworking machinery
 printing
 spraying
 robotics

15. Summary
 Measurement system: an important building block
 Sensors and transducers : definitions and difference
 Types of sensors
 Potentiometer sensors
 Principle of operation
 Construction and working
 Applications

16. Next
 Displacement, position and proximity sensors
 Strain gauge based sensors
 Capacitive elements
 Linear Variable Differential Transformer (LVDT)
 Eddy current based sensor
 Inductive proximity switch