1. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

2. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

3. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

4. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

5. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

6. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

7. TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

8. Target Long sensing distance: up to 30 metres with some devices Will detect all but very transparent materials Must be accurately aligned TransmitterReceiver Type : Through-beam Optical sensors (Through-beam)

9. Optical sensors (Retro-reflective)

10. Reflector (prismatic) TRTR Optical sensors (Retro-reflective) Type : Retro reflective Transmitter /Receiver

11. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

12. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

13. Reflector (prismatic) Target TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

14. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

15. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

16. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

17. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

18. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

19. Reflector (prismatic) TRTR Transmitter /Receiver Optical sensors (Retro-reflective) Type : Retro reflective

20. Reflector (prismatic) Sensing distance : 1/2 to 1/3 of through-beam type Not suitable for reflective or transparent targets Target should be larger than the reflector TRTR Type : Retro reflective Transmitter /Receiver Optical sensors (Retro-reflective)

21. Type : Diffuse Optical sensors (Diffuse)

22. Target TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

23. TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

24. TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

25. TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

26. TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

27. TRTR Transmitter /Receiver Optical sensors (Diffuse) Type : Diffuse

28. Transmitter /Receiver Sensing distance: much less than reflex type, actual distance depends on colour and reflective nature of the surface Larger targets result in longer sensing distances Not suitable for dirty environments TRTR Optical sensors (Diffuse) Type : Diffuse

29. Sensor is adjusted so that it does not ‘see’ the wall of the vessel. Capacitive sensor

30. As the level rises the fluid affects the sensor field. Capacitive sensor

31. Until the sensor switches. Capacitive sensor

32. Sensor symbols

33. + 18 to 30 Volts DC. 0 V Output Inductive Capacitive Optical Magnetic Ultrasonic Normally open Normally closed Sensor symbols

34. Sensor connection

35. Target Type: Through-beam Long sensing distance : up to 30 metres with some devices Will detect all but very transparent materials Must be accurately aligned TransmitterReceiver Optical sensors

36. Transmitter / Receiver Reflector (prismatic) Type: Retro-reflective Sensing distance : 1 / 2 to 1 / 3 of through- beam type. Not suitable for reflective or transparent targets Target should be larger than the reflector TRTR Optical sensors

37. Transmitter / Receiver Type : Diffuse Sensing distance : much less than reflex type, actual distance depends on colour and reflective nature of the surface Larger targets result in longer sensing distances Not suitable for dirty environments TRTR Optical sensors