Deck 19: Proximity Detectors

Question 1

How do ultrasonic detectors operate and what can they determine?

Answer 1

Ultrasonic detectors operate by emitting a pulse of high frequency sound and then detecting the echo when it bounces off an object. These detectors can be used to determine the distance to the object by measuring the time interval between the emission of the pulse and the return of the echo.

Question 2

Sensors should be mounted as close to other metals as possible.

Answer 2

False

Question 3

Some proximity detectors employ sound waves and can be used to detect the distance to an object or to determine the position of a object.

Answer 3

True

Question 4

Figure 19-09
The accompanying figure shows ______________________________ detectors used as position sensors.

Question 5

Proximity detectors are used to sense the presence of an object without physically touching it.

Question 6

One disadvantage of capacitive proximity detectors is that they have a very limited ____________________.

Question 7

Figure 19-03
The accompanying figure shows a detector that uses a tank circuit tuned to the frequency of the oscillator. This type of sensor is a(n) ____________________.

Question 8

Figure 19-02
In the accompanying figure, the presence of metal is causing a(n) ____________________ of voltage across the register.

Question 9

Why are many capacitive proximity detectors being used to replace mechanical limit switches?

Question 10

A(n) ____________________ is a device used to generate alternating current at a desired frequency.

Question 11

Figure 19-02
In the accompanying diagram, when the current flow through the resistor is decreased, what happens to the voltage?

Question 12

Capacitive proximity detectors depend on metal to operate.

Question 13

Proximity detectors used to sense all types of metals will sense nonferrous metals better than ferrous metals.

Question 14

If proximity detectors are used in areas that contain metal shavings or dust, an effort should be made to do what?

Question 15

Figure 19-05
In the circuit shown in the accompanying figure, what happens when a nonferrous metal, such as aluminum, copper, or brass, is placed near the sensor coil?