1. Magnetic Contactor For handling large current and voltage.
Can be used for interlock to prevent false and dangerous operations.

2. Magnetic Contactor Circuit

3. Manual Operated Switches
Controlled by hand
Include toggle switch, push button, selector switch, etc.

4. Selector Switch Circuit

5. Switches
DIP Switch
Limit Switch

6. Limit Switch Circuit
For Starting and stopping a motor in forward and reverse with limit switch providing over-travel protection

7. Temperature Switches
Or called Thermostat, to sense temperature changes, actuated by some specific temperature change

8. Pressure Switch To control pressure of liquid and gas
Actuated when a specified pressure is reached.

9. Pressure Switch Circuit

10. Level Switch To sense the height of a liquid. A float is attached
The rising and lowering of the float trips the level switch

11. Transducers and Sensors
Transducer convert energy from one form to another.
Sensors are transducer for detecting and measuring.

12. Sensors used in Manufacturing

13. Proximity Sensor
To detect the presence of an object without physical contact.
Inductive is actuated by metal object

14. Proximity Sensor

15. Inductive Proximity Sensor

16. Proximity Sensors Connections

17. Hysteresis

18. Capacitive Proximity Actuated by any dirt in their environment.
Usually supplement to the inductive proximity sensor when there is no metal available for the actuation.

19. Magnetic Switch
A magnetic switch also called reed switch, composed of two flat contact sealed in a glass tube.
As a permanent magnet approaches, the ends of the overlapped contact tab attract one another.

20. Light Sensor
Photovoltaic cell converts light energy directly into electric energy.
Photoconductive cell also called photo-resistive cell. Light energy falling on the cell will cause change in resistance

21. Photoelectric Sensor
Use a LED for the light source and phototransistor to sense the presence of light.
Two main types of photoelectric : - Reflective - Through Beam

22. Reflective Type
It is used to detect the light beam (visible, infrared, or laser) reflected from the target.

23. Through Beam
It is used to measure the change of light quality caused by the target crossing the optical axis.

24. Features of Photoelectric Sensor
Non contact detection – long service life
Almost any material – based quantity of light received
Long detection distance – reflective(1m), through beam (10m)
High response speed – 50us
Color Discrimination – based on absorption of its color
Highly accurate

25. Barcode Technology
Bar code system consists of : bar code symbol, a scanner , and a decoder.
Bar code symbol contains up to 30 characters encoded in a machine-readable form.

26. Bar code system Mostly based on UPC (universal product code)
UPC type (1 char)
Manufacturer or vendor ID (5 chars)
Item number (5 chars)
Check digit (1 char)

27. Barcode Scanner
A light source illuminates the bar code symbol, those bar absorb light , and spaces reflect light.
A photo detector collects this light in the form of an electronics signal pattern.
The decoder received the signal and converts these data into character data.

28. Ultra sonic Sensor
An ultrasonic sensor operates by sending sound waves toward the target and measuring the time it takes for the pulses to bounce back.
Its bounce back time proportional to the distance

29. Strain/Weight Sensor
A strain gauge transducer converts a mechanical strain into an electric signal.
Strain gauge are based on the principle that the resistance of a conductor varies with length and cross-sectional area.

30. Temperature Sensor

31. Thermocouple Most commonly used for temperature measurement.
It is a pair of dissimilar conductors welded or fused together at one end to form the “hot”, junction with the free ends available for connection to the “cold” or reference junction.
When temperature difference occurs, a small dc voltage is generated.

32. Non contact Temperature Sensor
Infrared radiation from the object surface generates hot spot on the thermocouple

33. Flow Measurement
Converts the kinetic energy that the fluid has into some other measurable form.
Turbine flow meter’s blades turn at a rate proportional to the fluid velocity.
Magnetic flow meter offers no restriction to flow. A coil set up a magnetic field, if a conductive liquid flows through this magnetic field, a voltage is induced

34. Velocity/RPM Sensor
The output of a generator varies with the speed at which the generator is driven.