Measurements & Instrumentation – Module 4 Proximity Sensors Measurements & Instrumentation – Module 4

Objectives Demonstrate understanding of the importance of sensors and the function of proximity sensors Identify types of proximity sensors and their applications demonstrate understanding of proximity sensor applications through experiments

Introduction Sensors have become increasingly important components used to acquire and transmit information in automated production systems. They are also used in a number of other real world applications. Sensors can be divided, according to the type of output signal, into binary sensors, also called switches, and analog sensors. Binary sensors produce a digital output (‘high’ or ‘low’), and analog sensors provide a varying or analog output.

Introduction Sensors are devices which can operate both by means of contact, or without contact; they are selected based on the requirement of the application. For example, the door at the entrance of the mall is equipped with an ultrasonic sensor that senses the presence of people and enables the door to open and close automatically.

Proximity Sensors Proximity sensors detect whether or not an object is located or present at a certain position. Sensors of this type operate electronically without contact. Several advantages of contactless proximity sensors are given below: 1) Precise and automatic sensing of position. 2) Contactless sensing protects objects from damage. 3) Fast response, and do not include moving parts which can wear out.

Proximity Sensor Applications Different types of proximity sensors are used in many areas of the industry, based on the application of position detection. Ultrasonic Sensor Optical Sensor Inductive Sensor Capacitive Sensor

Ultrasonic Sensors Ultrasonic sensors can detect solid, liquid, granular and powdery substances; they are used in applications where it is required to detect the object within a specified range. For example, an Ultrasonic sensor that is embedded in the front and/or rear bumpers of the car, helps to measure the distances to nearby objects at a low level. This provides feedback/warning to the driver regarding the obstacle in the form of an alarm, and thereby helps in preventing accidents.

Ultrasonic Sensors Applications Detecting the presence of a person and opening a door Detecting the presence of a car in a car wash station.

Ultrasonic Sensors Industrial Applications Sensing Liquid Levels Control of lifting vehicles

Optical Sensors Optical proximity sensors are used for counting boxes, breakage and jam detection etc. Counting Application: Different types of proximity sensors are used to count the number of items produced in production lines based on the material used in the application Counting Bottles Counting IC Chip Pins Counting Boxes Counting Packages

Detecting Metallic Chips Inductive Sensors Inductive proximity sensors are used to detect the presence of metals. Detecting Metallic Chips

Capacitive Sensors Capacitive proximity sensors are used to detect metal and even non-metallic objects such as wood, paper, liquid and so on. However, the detection range of inductive and capacitive proximity sensors is very small. Detecting Milk in Cartons

Lab Activities 1 and 2

Module Exc.