[4] Industrial Sensors

Industrial Sensor

a device that detects/measures a signal or stimulus from the real world and convert it into an electrical signal; detects a changing condition like temperature, pressure, position, weight, etc.

1. Limit Switches

2. Proximity Switches

3. Temperature Sensors

4. Other Industrial Sensors

Common Industrial Sensors

Limit Switch

an electromechanical device that detects the presence or absence of an object or monitors its position within a defined range with physical contact

Limit Switch

an industrial sensor that consists of an actuator mechanically linked to a set of contacts

Limit Switch

commonly used to detect positions of objects and parts of machines

1. Type of Actuator

2. Response Time

3. Electrical Ratings

4. Contact Type

5. Other Factors

Factors to Consider when Selecting and Installing Limit Switches

1. Plunger Type

2. Lever

3. Roller-Lever

4. Rotary

Type of Actuator in a Limit Switch

Plunger Type

a limit switch type of actuator that is activatedd when a direct push on top is applied

Lever

a limit switch type of actuator that is activated when an object pushes the lever

Roller-Lever

a limit switch type of activator that is activated when a horizontal object pushes it

Rotary

a limit switch type of actuator that is activated through a rotational movement of an object

1. Snap-Action Switch

2. Slow-Action Switch

3. Precision Limit Switch

4. Sealed/Heavy-Duty Limit Switch

Types of Limit Switch Response Time

Snap-Action Switch

a type of limit switch response time that changes states very quickly when triggered, regardless of the speed of actuation

Slow-Action Switch

a type of limit switch response time that operates proportionally to the actuator’s motion

Precision Limit Switch

a type of limit switch response time that offers highly accurate and repeatable position detection

Sealed/Heavy-Duty Limit Switch

a type of limit switch response type that is designed for harsh environments, often used in industrial settings

1. Voltage Rating

2. Current Rating

Limit Switch Electrical Ratings

Voltage Rating

a limit switch electrical rating that pertains to the maximum voltage that the contacts can handle

Current Rating

a limit switch electrical rating that pertains to the maximum current that the contacts can handle

1. SPST

2. SPDT

3. DPDT

Limit Switch Contact Types

1. Mounting and Size

2. Cost and Availability

3. Mechanical Durability

Other Factors to Consider when Selecting and Installing Limit Switches

Mounting Style

can be top-mounted, side-mounted, or adjustable mounting

Size and Space

a factor to consider when selecting and installing limit switch that ensures the switch fits the available space without interfering with other components

Proximity Switches

detect the presence of objects without physical contact

Proximity Switches

widely used in mechatronics, automation, and industrial control systems to detect objects, count items, or serve as position indicators

1. Inductive Proximity Sensor

2. Capacitive Proximity Sensor

3. Photoelectric Sensor

4. Magnetic (Reed) Switch

5. Ultrasonic Sensor

Types of Proximity Switches

Inductive Proximity Sensor

a non-contact sensor that detects metallic objects using electromagnetic fields

Inductive Proximity Sensor

used in industrial automation, robotics, and manufacturing processes due to their reliability and durability

Inductive Proximity Sensor

its sample applications include counting bottles, checking if bottles have caps, detecting presence of a broken drill bit, detecting presence of set screw on Hub for Speed or Direction Control, and detecting full open or closed valve position

Capacitive Proximity Sensor

non-contact sensor that detects both metallic and non-metallic objects such as plastics, wood, glass, liquids, and even powders

Capacitive Proximity Sensor

works by sensing the changes in capacitance when an object enter their detection field

Capacitive Proximity Sensor

its sample applications include detecting milk inside boxes, controlling fill level of solids in a bin, and detecting presence of caps on bottles

Photoelectric Sensors

position-sensing devices that use a modulated light beam that is either broken or reflected by the target

Photoelectric Sensors

wherein a light source (laser or LED) emits light, the receiver detects if there is a presence or absence of light and then the sensor generates an on/off signal depending on the type

Photoelectric Sensor

has farther range than capacitive and inductive

1. Thru-beam

2. Retro-reflective

3. Diffuse-reflective

Types of Photoelectric Sensors

Thru-beam Photoelectric Sensor

a photoelectric sensor wherein the emitter and receiver are installed opposite to each other and the light beam is continuously transmitted between them; when an object interrupts the beam, the receiver detects the change and triggers the output

Thru-beam Photoelectric Sensor

its sample applications include detecting packaging targets for conveyors, pins counting, and automatic doors

Retro-reflective Photoelectric Sensor

a photoelectric sensor wherein the emitter and receiver are housed together in one unit and a reflector is placed opposite the sensor so that the light beam bounces off of it and returns to the receiver; when the object blocks the light path, the output is triggered

Retro-reflective Photoelectric Sensor

its sample applications include bottle counting, parts detection, and product detection

Diffuse-reflective Photoelectric Sensor

a photoelectric sensor wherein the emitter and receiver are housed together in one unit and the object itself reflects the light back to the receiver; detection occurs when a change in reflected light intensity is noticed

Diffuse-reflective photoelectric sensors

its sample applications include hand detection in touchless dispensers, detecting fallen containers, and bottle presence detection

Magnetic (reed) Switch

a type of non-contact electrical switch that is activated by a magnetic field

Magnetic (reed) Switch

it is commonly used as a proximity sensor for pneumatic cylinder pistons

Ultrasonic Sensor

uses high-frequency sound waves (ultrasound) to detect objects

Ultrasonic Sensor

can detect both metallic and non-metallic objects and can measure the distance of an object from it

Ultrasonic Sensor

works on a principle siilar to RADAR or SONAR

Temperature Sensors

measure heat energy and convert it into a readable signal (electrical, mechanical, or digital)

Temperature Sensor

critical in industrial automation, manufacturing, process control, and HVAC systems to monitor and regulate temperature

Temperature Sensors

ensure safety, efficiency, and quality control in various applications, such as boilers, furnaces, food processing, and chemical plants

1. Thermocouples (T/C)

2. Resistance Temperature Detectors (RTDs)

3. Thermistors

Types of Temperature Sensors

Thermocouples (T/C)

widely used in high-temperature environments due to durability and fast response time; cost-effective compared to other sensors

1. Type K

2. Type J

3. Type T

4. Type R/S

5. Type N

Types of Thermocouples

Type K

a type of thermocouple that is commonly used in general industry, furnaces, and engines

Type J

a type of thermocouple that is commonly used in plastics and food processing

Type T

a type of thermocouple that is used in cryogenics and refrigeration

Type R/S

a type of thermocouple that is used in high-temperature metallurgy

Type N

a type of thermocouple that is used in aerospace and power plants

Resistance Temperature Detectors (RTDs)

a type of temperature sensor that has a higher accuracy and stability compared to thermocouples

Resistance Temperature Detectors (RTDs)

a type of temperature sensor used in precision measurement applications

1. PT100

2. PT1000

Common Types of Resistance Temeperature Detectors (RTD)

Thermistor

a type of temperature sensor that is cost-effective for low to medium temperature applications

Thermistors

a type of temperature sensor used in HVAC, medical devices, and battery monitoring

1. Negative Temperature Coefficient (NTC)

2. Positive Temperature Coefficient (PTC)

Types of Thermistor

NTC (Negative Temperature Coefficient)

a type of thermistor wherein resistance decreases as temperature increases

PTC (Positive Temperature Coefficient)

a type of thermistor wherein resistance increases as temperature increases

Temperature Sensor

its applications include monitoring oven temperature, measuring temperature of burner in the heater, and monitoring machine temperature

1. Strain Gauge

2. Pressure Sensor

3. Humidity Sensor

4. Float Switch

Other Industrial Sensors

Strain gauge

used to detect and measure weights and forces

Pressure sensor

used to detect change in pressure

Humidity sensor

used to detect and measure change in relative humidity

Float switch

used to detect level of liquids in tanks