Proximity sensors

1
Proximity sensors
Inductive
Capacitive
Optical Through-beam
Reed switch
Symbols
Optical Retro-reflective
Optical - Diffuse
Inductive magnetic
Connection
2
Optical sensors (Through-beam)
Type Through-beam
3
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
4
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
5
Optical sensors (Through-beam)
Type Through-beam
Target
Transmitter
Receiver
6
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
7
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
8
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
9
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
10
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
11
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
12
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
13
Optical sensors (Through-beam)
Type Through-beam
Transmitter
Receiver
14
Optical sensors (Through-beam)
Target
Type Through-beam
Transmitter
Receiver
Long sensing distance up to 30 metres with some
devices Will detect all but very transparent
materials Must be accurately aligned
15
Optical sensors (Retro-reflective)
16
Optical sensors (Retro-reflective)
Type Retro reflective
Transmitter /Receiver
Reflector (prismatic)
17
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
18
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
19
Optical sensors (Retro-reflective)
Target
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
20
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
21
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
22
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
23
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
24
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
25
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
Reflector (prismatic)
26
Optical sensors (Retro-reflective)
Type Retro reflective
T R
Transmitter /Receiver
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
27
Optical sensors (Diffuse)
Type Diffuse
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Optical sensors (Diffuse)
Target
Type Diffuse
Transmitter /Receiver
29
Optical sensors (Diffuse)
Type Diffuse
T R
Transmitter /Receiver
30
Optical sensors (Diffuse)
Type Diffuse
T R
Transmitter /Receiver
31
Optical sensors (Diffuse)
Type Diffuse
T R
Transmitter /Receiver
32
Optical sensors (Diffuse)
Type Diffuse
T R
Transmitter /Receiver
33
Optical sensors (Diffuse)
Type Diffuse
T R
Transmitter /Receiver
34
Optical sensors (Diffuse)
Type Diffuse
T R
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
35
Inductive sensors
36
Inductive sensors
High frequency magnetic field(300 to 800 kHz)
Active surface
Resonant circuit coil
LED indicator
Connection cable
37
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
38
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
39
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
40
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
41
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
42
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
43
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
44
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
45
Inductive sensors
Target
Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
46
Inductive sensors

• Will detect any conductive material
• Quoted distances are for mild steel
• Sensor performance can be affected by
• Temperature
• Target material
• Target dimensions

47
Reed switch
48
Reed switch
Glass Tube filled with nitrogen
Reed contacts
LED indicator
49
Reed switch
50
Reed switch
51
Reed switch
52
Reed switch
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Reed switch
54
Reed switch
55
Reed switch
24v
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Reed switch
24v
57
Reed switch
Interference from other magnetic fields must be
avoided. If positioned in mid stroke, switching
point will vary depending on direction of
approach. Maximum current must be limited to
avoid burning of the reed contacts.
58
Inductive magnetic sensor
59
Inductive magnetic sensor
Connection cable
LED Indicator
Resonant circuit coil
High frequency magnetic field
60
Inductive magnetic sensor
61
Inductive magnetic sensor
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Inductive magnetic sensor
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Inductive magnetic sensor
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Inductive magnetic sensor
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Inductive magnetic sensor
66
Inductive magnetic sensor
Inductive principle of operation - but only
reacts to magnetic fields Interference from other
magnetic fields must be avoided. Solid state
device - higher switching frequency - 1kHz
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Capacitive sensor
68
Capacitive sensor
Electrostatic field
Sensor is looking for a change in capacitance in
the active field
Active surface
Active electrode
Earth electrode
LED indicator
Adjusting screw
Connection cable
69
Capacitive sensor
Target
70
Capacitive sensor
71
Capacitive sensor
72
Capacitive sensor
73
Capacitive sensor
Detects any material denser than air (as long as
there is enough of it) Can be adjusted for
sensitivity Can be affected by dusty environments
74
Capacitive sensor
Sensor is adjusted so that it does not see the
wall of the vessel.
75
Capacitive sensor
As the level rises the fluid affects the sensor
field.
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Capacitive sensor
Until the sensor switches.
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Sensor symbols
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Sensor symbols
Inductive
Capacitive
18 to 30 Volts DC.
Optical
Output
Magnetic
Ultrasonic
Normally open
0 V
Normally closed
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Sensor symbols
Capacitive Sensor with Normally open function
18 to 30 Volts DC.
Output
0 V
80
Sensor connection
81
Sensor connection
24v DC

• PNP Type
• Output is Positive
• Positive switching

18 to 30 Volts DC
Output
0 V
0v
82
Sensor connection
24v DC

• NPN Type
• Output switches through to 0v
• Negative switching

18 to 30 Volts DC
Output
0 V
0v
83
Sensor connection
84
Sensor connection
Inductive
Capacitive
18 to 30 Volts DC.
Optical
Output
Magnetic
Ultrasonic
Normally open
0 V
Normally closed
85
Inductive sensor
Target

• Will detect any conductive material
• Quoted distances are for mild steel
• Sensor performance can be affected by-
• Temperature
• Target material
• Target dimensions.

Sensor
Oscillation Amplitude
Sensor output signal
ON OFF
86
Capacitive sensor
Detects any material denser than air.(as long as
there is enough of it) Can be adjusted for
sensitivity Can be affected by dusty environments
87
Optical sensors
Type Through-beam Long sensing distance up to
30 metres with some devices Will detect all but
very transparent materials Must be accurately
aligned
Target
Transmitter
Receiver
88
Optical sensors
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
T R
Transmitter / Receiver
Reflector (prismatic)
89
Optical sensors
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
T R
Transmitter / Receiver
90
Reed switch
Interference from other magnetic fields must be
avoided. If positioned in mid stroke, switching
point will vary depending on direction of
approach. Maximum current must be limited to
avoid burning of the reed contacts.
91
Inductive magnetic sensor
Inductive principle of operation - but only
reacts to magnetic fields Interference from other
magnetic fields must be avoided Solid state
device - higher switching frequency - 1kHz