Flex Automation Chapter 4

Ultrasonic sensors use sound waves with frequencies above ______________________________ kHz in order to detect the distance to an object.

16

The following symbol in an RLD represents a ____. A. temperature switch B. flow switch C. float switch D. pressure switch

A. temperature switch

In a relay device, you can find ____. A. multiple coils and NO or NC contactors B. one coil and multiple NO and NC contactors C. one coil and one NO contactor D. one coil and one NC contactor

B. one coil and multiple NO and NC contactors

You can use a PLC output port ____. A. to run a large motor B. to start a large motor C. to start a large conveyor D. to start a large generator

B. to start a large motor

There are ____. A. only active triangulation systems B. only passive triangulation systems C. active and passive triangulation systems D. None of the above.

C. active and passive triangulation systems

In a triangulation system, ____. A. distance is measured B. direction of the location of an object is detected C. both distance (range) and direction of an object is detected D. None of the above.

C. both distance (range) and direction of an object is detected

The following electrical symbol is classified as a ____. A. single-pole, single-throw, single-break B. single-pole, double-throw, single-break C. double-pole, double-throw, double-break D. double-pole, single-throw, double-break

C. double-pole, double-throw, double-break

The following electrical symbol is classified as a ____. A. double-pole, double-throw, single-break B. double-pole, double-throw, double-break C. double-pole, single-throw, double-break D. double-pole, single-throw, single-break

C. double-pole, single-throw, double-break

A(n) ______________________________ sensor detects an object through the change in the sensor's dielectric.

Capacitive

The two main sections of motor starters are ______________________________ and overload protection.

Contactors

In general, a relay consists of a magnetic core and its associated coil, ______________________________, spring, armature, mounting, and terminals.

Contacts

A(n) ______________________________ is typically used in the control of low-power circuits or other devices.

Control Relay

A double-pole, double-throw (DPDT) switch has ____. A. 3 terminals B. 4 terminals C. 5 terminals D. 6 terminals

D. 6 terminals

Which of the following statements is false? A. A liquid level switch is sometimes called a float switch. B. A proximity switch can be used instead of a limit switch. C. A proximity switch can be used instead of a level switch. D. A flow switch can replace a pressure switch.

D. A flow switch can replace a pressure switch.

A solenoid may be used to control the ____. A. movement of a mechanical device B. flow of liquid or gas C. closing of a set of electrical contacts D. All of the above.

D. All of the above.

Optical sensors can use ____. A. visible light B. infrared light C. laser light D. All of the above.

D. All of the above.

There are electronic sensors that can be used to mimic ____. A. human sight and hearing B. human touch and taste C. human smell and hearing D. All of the above.

D. All of the above.

To protect an electric motor, one can use a ____. A. temperature overload relay B. magnetic overload relay C. temperature and magnetic overload relay D. All of the above.

D. All of the above.

Which of the following is an example of an indicator? A. Pilot light B. Ammeter C. Voltmeter D. All of the above.

D. All of the above.

A single-pole, single-throw (SPST) switch connected to a discrete input can send _____. A. an ON or an OFF signal to the PLC B. a logic 1 or a logic 0 to the PLC C. only an ON signal to the PLC D. Both A and B.

D. Both A and B.

An electronic proximity sensor can have a(n) ____. A. LED and phototransistor B. magnetic field and coil C. transmitter and receiver D. Both A and C.

D. Both A and C.

A relay coil in a low-power control circuit is energized by applying ______________________________ voltage to the coil terminals.

DC

Pushbuttons and switches, also called ______________________________ input devices, are independent devices that either allow or disallow electric current to flow through them.

Discrete

TRUE OR FALSE: Flow switches are used to open and close contacts in response to changes in liquid level.

False

TRUE OR FALSE: Hall effect sensors produce sound above the normal human hearing threshold of 16 kHz and use this sound to detect the distance to an object.

False

Used to open and close contacts in response to change in liquid level

Float Switch

Detects specific flow rates

Flow Switch

A(n) ______________________________ switch is used in factory environments as an emergency or contact switch when a worker is using both hands for assembling a product.

Foot

Used as emergency or contact switches

Foot Switch

A(n) ______________________________ sensor detects the presence of metallic objects by measuring changes in magnetic fields.

Inductive

Consists of an actuator that is mechanically linked to a set of contacts

Limit Switch

A(n) ______________________________ switch is generally used to detect the liquid level in a chemical tank or water well.

Liquid Level

A(n) ______________________________ simply turns a motor on and off.

Motor Starter

A(n) ______________________________ sensor produces a small AC voltage signal.

Piezoelectric ultrasonic

Detects low and high pressure in hydraulic and pneumatic systems

Pressure Switch

Uses a light-emitting diode (LED) and a phototransistor

Proximity Switch

A relay is a device that acts on the same basic principle as the ______________________________ switch.

Reed

Slowly accelerating a motor from standstill to operating speed is referred to as a(n) ______________________________.

Soft Start

A(n) ______________________________ is a control device that uses electromagnetism to convert electrical energy into mechanical motion.

Solenoid

Momentary pushbuttons, also called ______________________________ pushbuttons, change their states from open to closed or from closed to open.

Spring-Loaded

Detects a specific present temperature

Temperature Switch

TRUE OR FALSE: A proximity switch uses a light-emitting diode (LED) and a phototransistor.

True

TRUE OR FALSE: A relay is a device that acts on the same basic principle as the reed switch.

True

TRUE OR FALSE: Inductive sensors detect the presence of nearby metallic objects by measuring changes in magnetic fields.

True

Power relays are often called ______________________________.

contractors

In an optical sensor, a(n) ______________________________ is used to generate light beams in the visible and invisible spectrums using light-emitting diodes (LEDs) and laser diodes.

emitter

Two types of motor overload relays are available in industry: temperature overload relays and ______________________________ overload relays.

magnetic

A(n) ______________________________ pushbutton or switch is always closed—until it is forced to open.

normally closed

A(n) ______________________________ pushbutton or switch is always open—until it is forced to close.

normally open

The term ______________________________ refers to the number of places in which a switch opens or breaks the circuit.

pole or poles