Prox Switches and Sensors Quiz

When a nonconductive target is within the sensing range of a capacitive proximity detector, _____ which causes the capacitance to __

the dielectric constant changes, increase

A capacitive proximity detector senses _____

both metallic and nonmetallic materials

A conductive target changes the value of the capacitor in a capacitor proximity detector by ______

adding an additional plate

Which materials can be detected by a capacitive proximity detector?

liquids, granular solids, ferrous metal, non-metallic solids, powder

The span of an analog ultrasonic sensor is

the magnitude of its sensing range

Ultrasonic proximity sensors use ____ to detect the presence or absence of objects

high-frequency sound waves

Ultrasonic sensors are only effective in detecting solid objects and cannot detect liquids or gases. T/F

False

Ultrasonic sensors have a shorter range compared to infrared sensors. T/F

True

Ultrasonic sensors are unaffected by ambient light, making them suitable for outdoor applications. T/F

True

Ultrasonic sensors can measure the distance to an object as well as detect its presence. T/F

True

Temperature changes can affect the speed of sound, which may slightly impact the accuracy of ultrasonic sensors. T/F

True

Ultrasonic sensors can detect objects through transparent materials like glass or plastic. T/F

False

Ultrasonic sensors are commonly used in automotive applications for parking assistance and obstacle detection. T/F

True

Ultrasonic proximity sensors can measure

the level of liquid in a tank, the presence of metallic objects, and the level of cereal in an open box

What type of waves do ultrasonic proximity sensors use for detection?

Sound waves

Main function of an ultrasonic proximity sensor

measuring position of an object

Typical range of detection for ultrasonic sensors

Several meters

Factor that can affect accuracy of ultrasonic sensors

Material density and material size

One of the factors that determine the voltage amplitude of a Hall-effect device is its physical size. t/f

True

The voltage amplitude produced by the linear Hall-effect device is inversely proportional to its distance from the magnetic target. T/F

True

Hall-effect sensors vs inductive detectors switching frequency

Hall-effect sensors switch at higher frequencies

The Hall-effect sensor detects ____

magnetic fields

Sensing distance of an iron target from an inductive proximity detector proportional to thickness T/F

False

The recommended space between the target and sensor head of an inductive proximity sensor is half the nominal sensing distance. t/f

True

The demodulator in an inductive proximity detector is a filtered half-wave rectifier T/F

True

A linear inductive proximity detector uses a Schmitt trigger in its internal circuitry T/F

False

When target is within range of an inductive proximity detector, the sensor's oscillator

loses power

A _____ Inductive sensor with the longer sensing range

non-shielded

The sensing distance of a foil target made of a non-ferrous material from an inductive proximity detector is __________ a thicker target made of the same material.

greater than

Inductive sensors with _____ should used for high speed switching (e.g., counting gear teeth)

small diameters

An inductive proximity detector senses _____

metallic materials

An inductive sensor head flush mounted into a metal plate does not need a shield around its coil because the surrounding material automatically provides the shielding. T/F

False

The recommended diameter of the inductive proximity sensor head is twice the width of the target. T/F

False

A Ferrous target _____ will be detected at greatest sensing range by an inductive proximity sensor (same cross sectional area as the section head or twice the cross section area as the sensor head)

neither, they are the same

Retroreflective sensors can detect a shiny target if placed at a skewed angle T/F

True

A dirty optical lens reduces ability of all light detection methods to differentiate light levels T/F

True

Retroreflective sensors can detect translucent objects at a skewed angle T/F

False

Infrared is a ___ light to the human eye

invisible

What determines color difference in light?

frequency

what type of light detection is used for detects and counts small objects at a rapid pace / detects an object from a long distance away (opposed sensing, retroreflective scanning, diffuse sensing, convergent sensing or specular sensing)

opposed sensing

what type of light detection is used for detecting a clear object (opposed sensing, retroreflective scanning, diffuse sensing, convergent sensing or specular sensing)

diffuse sensing

what type of light detecting is used for detecting an object at a specific distance (opposed sensing, retroreflective scanning, diffuse sensing, convergent sensing or specular sensing)

convergent sensing

what type of light detecting is used for detecting an object from a long distance away (opposed sensing, retroreflective scanning, diffuse sensing, convergent sensing or specular sensing)

opposed sensing

what type of light detection is used for detecting an object that does not have a flat surface (opposed sensing, retroreflective scanning, diffuse sensing, convergent sensing or specular sensing)

convergent sensing

If only 25 percent of the light produced by an emitter is received by the detector due to unclear air, an excess gain of __________ is required to overcome the loss of light.

4

Diffuse method of light detection uses the ____ mode to detect an object

dark-to-light

Retroreflective method of light detection mode

light-to-dark

A light curtain is used for ____

counting applications and detect the size of an object

Detection method used to monitor clear plastic cellophane

diffuse

Object to be detected by an industrial detection sensor

target

Effect of oil or film on sensor head

affects capacitive and photoelectric types, but not inductive

The differential travel property of a proximity sensor is that the target must be __________ to turn on than to turn off.

closer

Factors determining capacitor ability to detect target presence

dimension, shape, distance, position

Proximity detectors are capable of producing a linear output signal that is inversely proportional to the distance of the target to the sensor. t/f

True

A sensor that is designed to detect an object exclusively in
front of the sensor head uses the approach

axial

A limit switch is coil activated like a solenoid or relay T/F

False

Function of a limit switch

open or close a set of contacts

Applications of limit switches

detecting position of object, detecting size of object, counting parts, preventing movement of an object outside a safe zone

If a film of oil or dirt forms on the head of a sensor, it will not affect the operation of the inductive type, but it may affect the capacitive type. t/f

True