I. Prereading Questions

1. What is a proximity sensor?

2. How proximity sensors work?

3. What is the application of proximity sensor?

II. Reading Text

PROXIMITY SENSOR

A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact.

A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor always requires a metal target.

The maximum distance that this sensor can detect is defined "nominal range". Some sensors have adjustments of the nominal range or means to report a graduated detection distance. Proximity sensors can have a high reliability and long functional life because of the absence of mechanical parts and lack of physical contact between sensor and the sensed object.

Proximity sensors are also used in machine vibration monitoring to measure the variation in distance between a shaft and its support bearing. This is common in large steam turbines, compressors, and motors that use sleeve-type bearings. International Electrotechnical Commission (IEC) 60947-5-2 defines the technical details of proximity sensors. A proximity sensor adjusted to a very short range is often used as a touch switch.

There are several types of proximity sensor which are used according to the need,

material detection and many other things. To classify them here are its types:

Inductive Proximity Sensors 

Device which generates output signal or electrical signal when metal objects are either

inside or entering into its sensing area from any direction. The metal object above includes iron,

aluminum, brass, copper, etc with varied sensing distances.

Other factors which affect Proximity sensors: flat targets are preferable, targets larger than the

sensing face may increase the sensing distance. First inductive proximity sensor was introduced

in the mid 60’s.

Capacitive Proximity Sensors

It can also detect metals but along with it can also detect resins, liquids, powders, etc.

This sensor working can vary accordingly covering material, cable longness, noise sensitivity. Its

sensing distance also varies according to factors such as the temperature, the sensing object,

surrounding objects, and the mounting distance between Sensors. Its maximum range of sensing

is 25 mm.

Magnetic Proximity Sensors

Proximity Sensors have no electrical noise effect and it can work on DC, AC, AC/DC,

DC. Again sensing distance can vary due to factors such as the temperature, the sensing object,

surrounding objects, and the mounting distance between Sensors. This type of sensors has

highest sensing range up to 120 mm. These sensors have been used in various devices like

mobile phones, tablets, security appliances, etc. These days it’s mostly used on mobile phones in

order to make it more functional, responsive and useful.

As mentioned above , this sensor works based on the distance to the object sensor , when

no metal object approaching this with a very close distance of 5 mm for example , then the

sensor will work and connect the ignition , then through the supplied cable can be connected to

other devices such as indicator lights , relays , and others . At the time of these sensors are

working or detect the presence of metal ( iron ) it will be marked with a small red light or green

is at the top of the sensor , making it easier for us to monitor the sensor or when doing preventive

maintenance .

Almost every machine - existing production machinery in any industry, be it small or

large industries, using a sensor of this type, because in addition to practical, this sensor is

resistant to impact or shock, but it is easy when doing maintenance or replacement, because it

has been designed so by the manufacturer, as for one example of the use or application of this

type of sensor is used to detect the motion of the cylinder up or down on an engine or drive.

Proximity Sensor Applications

Many applications use proximity sensors, of which the object or a metal detector in the

industry. Additionally this sensor is used also as a means of security or home environment that is

applied as an alarm.

III. Glossary-Summary

A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor always requires a metal target.

The maximum distance that this sensor can detect is defined "nominal range". Some sensors have adjustments of the nominal range or means to report a graduated detection distance.

1. Nominal range : Jarak Nominal

2. Return signal : Sinyal Balik

3. Noise : Gangguan

4. Ignition : Pemicu

5. Maintenance : Perbaikan / Peremajaan

IV. 10 True and False Statements

1. A proximity sensor is a sensor able to detect the presence of nearby objects

without any physical contact. [ True ]

2. A proximity sensor often emits an electromagnetic field or a beam

of electromagnetic radiation. [ True ]

3. Inductive proximity sensors are the preferred choice for the majority of

applications requiring accurate, non-contact detection of metallic objects in

machinery or automation equipment. [ True ]

4. Electromagnetism is one of the basic principle behind proximity sensors

operation. [ True ]

5. when no metal object approaching this with a very close distance, then the sensor will

work and connect the ignition , then through the supplied cable can be connected to

other devices [ True ]

6. The proximity sensor has advantages in terms of high ability and long service life

because these sensors have mechanical parts directly to the object box. [ False ]

Correct: proximity sensor don’t have mechanical parts directly to the object box.

7. Magnetic Proximity Sensors have electrical noise effect [ False ]

Correct: Proximity sensor don’t have electrical noise effect

8. The basic principle behind Proximity sensors operation is mechanism. [ False ]

Correct: The basic principle behind Proximity sensors operation is

electromagnetic

9. Proximity sensors will work when the object energized by DC voltage. [ False ]

Correct: if object energized by DC voltage, it does not affect the proximity

sensor

10. Magnetic Proximity sensors only work on DC voltage. [ False ]

Correct: Proximity Sensors can work on DC, AC, AC/DC, DC.

V. Question and Answer

1. What is the application of proximity sensor?

Answer: Many applications use proximity sensors, of which the object or a metal

detector in the industry. Additionally this sensor is used also as a means of security or home

environment that is applied as an alarm.

2. What the differences of capacitive proximity sensors and inductive proximity

sensors?

Answer: Inductive Proximity Sensors = Device which generates output signal or

electrical signal when metal objects are either inside or entering into its sensing area from any

direction. The metal object above includes iron, aluminum, brass, copper, etc with varied sensing

distances. Other factors which affect Proximity sensors: flat targets are preferable, targets larger

than the sensing face may increase the sensing distance. First inductive proximity sensor was

introduced in the mid 60’s. Capacitive Proximity Sensors = It can also detect metals but along

with it can also detect resins, liquids, powders, etc. This sensor working can vary accordingly

covering material, cable longness, noise sensitivity. Its sensing distance also varies according

to factors such as the temperature, the sensing object, surrounding objects, and the mounting

distance between Sensors. Its maximum range of sensing is 25 mm.

3. What parts of proximity sensors?

Answer: coil, infrared sensor

4. How the proximity sensor can work?

Answer: When anything comes in the range of Proximity sensor it flash out

infrared beam and monitors reflections. When sensor senses reflections it

confirms that there’s an object nearby.

5. Why we must make sure that the wires are connected to the right source voltage?

Answer: because proximity sensor can work on DC, AC, AC/DC voltage, if we

wrong give source voltage, proximity sensor will be broken.

6. When the proximity sensor was used?

Answer: if we want to run electrical devices automatically with sensors

7. How many types of Proximity Sensor?

Answer: there are 3 types of proximity sensor. Magnetic proximity sensor,

Inductive proximity sensor, and capacitive proximity sensor.

8. What's the meaning of sensing distance?

Answer: Detection distance is, distance from the reference position (reference

surface) to the measured operation (reset) when the standard sensing object is

moved by a particular method.

9. How to set the sensing distance

Answer : Distance from the reference surface that allows the use of a stable,

including the effects of temperature and voltage, to the position of the object

(standard) sensing transit. It is approximately 70% to 80% of the distance (the

value of) a normal sensing.

10. Why proximity sensors have a high reliability?

Answer: Proximity sensors can have a high reliability and long functional life

because of the absence of mechanical parts and lack of physical contact between

sensor and the sensed object.

VI. Synonym

Directly to : immediately to ( langsung )

Maintenance : repair ( perbaikan )

Mounted on : posted on ( terletak pada )

Noise : interference ( gangguan )

Compatible : Suitable (cocok)

Set : Determine ( Menentukan )

Made up : set up( tersusun )

Reliability : endurance ( ketahanan )

Trigger : spark ( pemicu )

To generate : to produce ( menghasilkan )