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What is the definition of actuator?

The part of a limit switch that comes into contact with an object and triggers the switch. Limit switch actuators come in different styles: rotary lever, fork, plunger, flexible loop, and spring rod.

Learn more about actuator in the class "Limit Switches and Proximity Sensors 360" below.

Limit Switches and Proximity Sensors 360

Motor Controls Department

Class Information

Tooling U classes are offered at the beginner, intermediate, and advanced levels.
The typical class consists of 12 to 25 lessons and typically requires at least two hours of instruction time.

Class Name	Limit Switches and Proximity Sensors 360
Description	This class covers the properties and functions of limit switches and inductive and capacitive proximity sensors, as well as hall effect sensors.
Prerequisites	460210 460220
Difficulty	Advanced
Number of Lessons	16

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Class Outline

Class Objectives

Objectives

The Role of Sensors

Limit Switches

Limit Switch Classifications

Limit Switch Actuators

Limit Switch Operation

Limit Switch Mounting

Limit Switch Applications

Proximity Sensors

Inductive Proximity Sensors

Inductive Proximity Sensor Range

Capacitive Proximity Sensors

Proximity Sensor Installation

Hall Effect Sensors

Pros and Cons of Limit Switches and Proximity Sensors

Summary

Define sensors.

Describe limit switches.

Describe limit switch classifications.

Describe limit switch actuators.

Describe limit switch operation.

Describe best practices for mounting limit switches.

Describe limit switch applications.

Define proximity sensors.

Describe inductive proximity sensors.

Identify factors influencing the sensing range of inductive proximity sensors.

Describe capacitive proximity sensors.

List best practices for installing proximity sensors.

Describe Hall effect sensors.

List the advantages and disadvantages of limit switches and proximity sensors.

Class Vocabulary

Term	Definition
active actuation	A type of Hall effect sensor actuation in which the sensor is stationary and the magnet is movable. Hall effect sensor actuation may be active or passive as required by the sensing application.
actuator	The part of a limit switch that comes into contact with an object and triggers the switch. Limit switch actuators come in different styles: rotary lever, fork, plunger, flexible loop, and spring rod.
amplitude	The maximum height or maximum depth of a wave. Amplitude measures the intensity of a signal.
body	The part of a limit switch that contains electrical contacts. A limit switch body is a separate, enclosed unit that protects the circuitry and allows the wiring to stay in place if the head of the switch is replaced
capacitive proximity sensor	A type of proximity sensor that senses the stored electrical charge of a target by detecting changes in an electrostatic field. Capacitive proximity sensors are typically used in bulk handling machines, level detectors, and package detection.
capacitor	An electrical or electronic part that stores electrical charges.Two metal plates form the capacitor of a capacitive proximity sensor.
contact bounce	The action that occurs when electrical contacts close with such force that they slam against each other and bounce away again. Contact bounce is undesirable because it can create secondary arcs and reduce contact life.
contacts	Conductive metal parts in an electrical circuit that open or close the circuit by coming in contact with or separating from each other.
cross-talk	Interference between two sensors when the signal from one sensor is unintentionally picked up by another sensor nearby. Cross talk can cause poor sensor performance or false outputs.
dielectric constant	The stored electrical charge of an object.
differential travel	The distance between the operating position and release position of a limit switch actuator.
eddy current	A magnetic current created by sensor vibration that flows out and around the sensor head.
ferrous metal	Made of or containing iron.
flexible loop actuator	A type of limit switch actuator that resembles a loop.
fork style actuator	A type of limit switch actuator with a two-pronged lever that resembles a "V," with a roller at the top of each end.
free position	The starting position of a limit switch actuator before it comes into contact with an object.
gravity return switches	A type of limit switch that has no spring return mechanism and requires the weight of the lever arm to reset the contacts. Gravity return switches are used on conveyors with small or lightweight objects that require very low forces of operation.
Hall effect sensor	A type of proximity sensor that generates voltage in response to the proximity of a magnetic field. Hall effect sensors are used for detecting metal objects that are among or within other metal objects.
hazardous location switches	A class of limit switches used in environments where they may be exposed to corrosive chemicals or possible explosions. Hazardous location switches are constructed with thick, heavy materials and use contacts that are encapsulated to avoid electrical energy being exposed to the elements.
head	The top part of a limit switch that holds the actuator. Limit switch heads are removable for easy replacement.
IEC	The International Electrotechnical Commission. The IEC governs electrical equipment standards in Europe and all other international countries.
inductive proximity sensor	A type of proximity sensor that uses an electromagnetic field to detect metal targets. Inductive proximity sensors are often shielded to improve sensor output.
limit switch	A type of mechanical sensor that requires physical contact to detect the presence or absence of an object. Limit switches are the first type of sensor to be used.
maintained actuation	A type of limit switch actuation that keeps the actuator at operating position until it is forcibly moved in the opposite direction. Fork style actuators are used for this type of actuation.
momentary actuation	A type of limit switch actuation that rotates the actuator from the free position through all the other positions, until it finally returns to the free position. Momentary actuators are spring loaded so that the contacts return to their normal position once the force is removed.
NEMA	The National Electrical Manufacturers Association. NEMA sets standards for equipment used in the United States.
neutral position switches	A type of limit switch that allows two different signals and responses, depending on the direction of actuation. When the lever is moved in a clockwise direction, a set of contacts is actuated. A second set of contacts is actuated when the lever moves in a counterclockwise direction.
operating distance	The distance of the sensor from the target while operating. Some sensors have ranges as small as a few millimeters, while others can detect objects from hundreds of feet away.
operating position	The position that a limit switch actuator reaches before triggering a set of contacts to open or close.
oscillator	A type of crystal that creates a constant periodic pulse. Oscillators are often used in solid state and electronic devices.
overtravel position	The distance beyond the operating position that a limit switch actuator can move without resetting the contacts.
passive actuation	A type of Hall effect sensor actuation in which the sensor is movable and the magnet is stationary. Hall effect sensor actuation may be passive or active as required by the sensing application.
plunger type actuator	A limit switch actuator in the shape of a depressible button or pin.
precision limit switches	A class of limit switches used for applications that require repeatable accuracy within a small range. For example, a precision limit switch would be used to return an electronic scale to its original start position (zero) after an object has been weighed.
pretravel position	The distance a limit switch actuator moves between the free position and the operation position.
proximity sensor	A solid state device that uses an electronic sensing field to detect the presence of an object. Proximity sensors do not have physical contact with the target.
radiated field	A field that flows out and around the sensor head in a circular or semicircular pattern.
release position	The position that a limit switch actuator reaches midway between the free position and pretravel position.
release travel	The distance from the release position back to the free position of a limit switch actuator.
rotary lever actuator	A type of limit switch actuator that uses a lever with a roller at the end. The lever can be long or short to suit the application.
safety cable pull switch	A type of limit switch that allows the operator to pull on it and stop the machinery in the event of an emergency. Safety cable pull switches are used in conveyor-type operations where moving parts and machinery may be dangerous to the operator.
safety guard switch	A type of limit switch that requires the operator to insert a key into a slot in the switch before the switch will work. Safety guard switches are used for operating dangerous machines.
sensing field	The area of the electronic or magnetic field that forms around the head of a sensor.
sensor	A device that detects the presence or absence of an object, or certain properties of that object, and provides feedback. Common sensor applications include parts detection, counting, and positioning, motion, speed, feed, and jam control, and parts diverting.
shunt	An opening that allows passage. Shunts in metal devices expose Hall effect sensors to magnetic fields.
solid state device	A device that functions by means of electronic components without the use of moving parts.
spring rod actuator	A type of limit switch actuator with a long, narrow bar that bends on contact, then bounces back to its original position.
standard industrial limit switches	A class of limit switches used in harsh industrial environments where they may be exposed to oil, grease, dirt, shock, vibration, or high-pressure washes.
switching rate	The speed at which a limit switch opens or closes a set of contacts after initial actuation.
two step switch	A type of limit switch set to activate one set of contacts when the lever rotates 10°, and a second set when the lever rotates 20°. Two step switches are used to detect height, position, and orientation of an object, and they allow a secondary operation.

What is the definition of actuator?

The part of a limit switch that comes into contact with an object and triggers the switch. Limit switch actuators come in different styles: rotary lever, fork, plunger, flexible loop, and spring rod.Learn more about actuator in the class "Limit Switches and Proximity Sensors 360" below.

Limit Switches and Proximity Sensors 360

Motor Controls Department

The part of a limit switch that comes into contact with an object and triggers the switch. Limit switch actuators come in different styles: rotary lever, fork, plunger, flexible loop, and spring rod.

Learn more about actuator in the class "Limit Switches and Proximity Sensors 360" below.