Question 1

A relay usually will have only one coil but a number of different contacts.

Accepted Answer

A relay typically has one coil to control multiple contacts.

Question 2

Reed switches are activated by magnetism.

Accepted Answer

Reed switches are designed to be activated by a magnetic field. When a magnetic field is present, the switch contacts close, allowing electrical current to flow through the switch.

Question 3

Changes to dual-in-line package (DIP) switch settings are made mainly during installation.

Accepted Answer

Changes to DIP switch settings are typically made during the installation process to configure the device or system according to specific requirements. Once the device or system is in use, changes to DIP switch settings are less common.

Question 4

The programmed latching relay instruction is retentive; that is, if the relay is latched, it will unlatch if power is lost and then restored.

Accepted Answer

A programmed latching relay instruction is retentive, meaning it maintains its state (latched or unlatched) even if power is lost and then restored.

Question 5

In a magnetic motor starter, the control circuit is required to handle the full load current of the motor.

Accepted Answer

The control circuit in a magnetic motor starter only handles the small control current for the starter coil, not the full load current of the motor. The power circuit of the starter handles the full load current of the motor.

Question 6

A normally closed (NC) relay contact is closed when current flows through the coil.

Accepted Answer

A normally closed (NC) relay contact is normally closed when there is no current flowing through the coil. It opens when the coil is energized.

Question 7

In general, control relay contacts are designed to handle higher currents than contactors.

Accepted Answer

Contactors are designed to handle higher currents than control relay contacts.

Question 8

A small current flows through a solid-state proximity sensor even when the output is turned OFF.

Accepted Answer

This is true because even when the output of a solid-state proximity sensor is turned OFF, a small current may still flow through it due to leakage or residual capacitance.

Question 9

Weight strain gauges operate by detecting small changes in temperature.

Accepted Answer

The answer of Weight strain gauges operate by detecting small...

Question 10

Proximity switches usually sense the presence or absence of a target by means of physical contact.

Accepted Answer

Proximity switches do not require physical contact with the target. They are designed to sense the presence or absence of the target within a certain distance without making physical contact.

Question 11

An electromechanical relay uses electromagnetism to operate contacts.

Accepted Answer

An electromechanical relay works by using an electromagnet to move one or more contacts to make or break a circuit.

Question 12

Fiber optic sensor systems are completely immune to all forms of electrical interference.

Accepted Answer

Fiber optic sensor systems use light to transmit information, therefore they are not affected by electromagnetic interference, which is a common problem with traditional electrical sensors.

Question 13

Ultrasonic sensors operate using high-frequency light waves.

Accepted Answer

Ultrasonic sensors operate using high-frequency sound waves, not light waves.

Question 14

Encoders are used in applications where positions have to be precisely determined.

Accepted Answer

Encoders are used in applications such as robotics, industrial automation, and CNC machines where precise positioning is crucial.

Question 15

All servo motors operate in open loop.

Accepted Answer

Servo motors can operate in open loop or closed loop. In open loop operation, there is no feedback to verify that the desired position or speed has been reached. In closed loop operation, the motor continuously receives feedback and adjusts its position or speed accordingly.

Question 16

An inductive proximity sensor is actuated by conductive and nonconductive materials.

Accepted Answer

An inductive proximity sensor is actuated by metallic objects due to its operating principle based on electromagnetic induction, and it does not detect nonconductive materials.

Question 17

A through-beam photoelectric sensor is used to detect the light beam reflected from a target.

Accepted Answer

A through-beam photoelectric sensor emits a light beam and detects if the light beam is interrupted by a target. It does not rely on the target reflecting the light beam back to the sensor.

Question 18

Latching relays are used when it is necessary for contacts to stay open and/or closed, even though the coil is momentarily energized.

Accepted Answer

Latching relays have two stable states and will remain in the last state until the coil is energized again, causing it to switch to the opposite state. This allows the contacts to stay open or closed without continuous power to the relay coil.

Question 19

LED light sources used in photoelectric sensors normally emit a continuous beam of light.

Accepted Answer

LED light sources used in photoelectric sensors emit a continuous beam of light.

Question 20

A selector switch is rotated to open and close contacts.

Accepted Answer

A selector switch is designed to rotate and select between different positions, which in turn opens and closes different sets of contacts.

Quiz 6: Developing Fundamental Plc Wiring Diagrams and Ladder Logic Programs