Question 1

How are the overload contacts connected in the logic circuit described in this chapter?

Accepted Answer

The normally closed overload contacts for starters 1M and 2M are connected in series with the appropriate starter. It is common practice by many industries to leave the overload contacts hard wired to the starter coil to ensure that the starter will de-energize in the event of an overload. Some manufacturers of motor control equipment provide a second overload contact that is normally open. This contact can be used as an input to the PLC and placed in the logic of the circuit. In this example, however, it is assumed that the overload relay contains a single normally closed contact that will remain hard wired to the coil. The common output terminal is connected to the hot or ungrounded power conductor and the other side of each coil is connected to the neutral or grounded power conductor.

Question 2

How is the operation of motor start coil 1M controlled in the example presented in this chapter?

Accepted Answer

The first step will be to draw a logic diagram that will control the operation of motor starter coil 1M. Because coil 1M is connected to output 17, coil number 17 will be used for coil 1M. Note that the on-off switch is connected to input 1. Therefore, contact 1 will be controlled by the on-off switch. When the switch is turned on, power will be provided to input terminal 1 and the normally open contact labeled 1 will close. The pressure switch is connected to input 2 and the auto terminal of the selector switch is connected to input 4. Since the control relay is to be assigned coil number 100, the CR1 contact is labeled 100. The normally closed 2M3 contact is labeled 18 because 2M motor starter coil is connected to output terminal 18. The normally closed overload contact (OL1) is not shown in the logic diagram because it is hard wired to the starter coil. The 1M2 contact connected in parallel with the normally closed CR1 contact is labeled 17 because output 17 controls the operation of 1M starter coil.

Question 3

When power is applied to an input, it will cause the contact assigned to that input to ____.
A) activate a push-button
B) close
C) open
D) change state

Accepted Answer

D

Question 4

A PLC assumes inputs to be ____ when a program is loaded into memory.
A) set
B) high
C) low
D) off

Accepted Answer

The answer of A PLC assumes inputs to be ____...

Question 5

The ____ input terminal is connected to the neutral or grounded power conductor.
A) common
B) L1
C) L2
D) tenth

Accepted Answer

The common input terminal is typically connected to the neutral or grounded power conductor.

Question 6

Describe the circuit considered in this chapter.

Accepted Answer

The answer of Describe the circuit considered in this chapter....

Question 7

In a logic diagram, each line of logic must end with a ____.
A) circuit
B) coil
C) pump
D) switch

Accepted Answer

The answer of In a logic diagram, each line of...

Question 8

Given that the internal clock that controls the operation of timers operates in 0.1-second intervals, what value do you have to program in order to get a one-second delay from the timer?
A) 0.1
B) 1.0
C) 10
D) 100

Accepted Answer

Since the internal clock operates in 0.1-second intervals, to get a one-second delay we need to program the timer for 10 intervals (0.1 x 10 = 1). Therefore, the correct choice is C) 10.

Question 9

A selector switch can be set to any of ____ operating modes.
A) one
B) two
C) three
D) four

Accepted Answer

A selector switch can typically be set to three different operating modes, which are indicated on the switch itself. It is unlikely for a selector switch to have only one or two operating modes, and four would be an unusual number. Therefore, the best choice is C, three.

Question 10

A(n) ____ occurs when it is possible for one contact to open before another closes or for one contact to close before another opens.
A) bypass
B) contact race
C) off-delay
D) on-delay

Accepted Answer

This is known as a contact race, which can lead to unpredictable and undesirable behavior in a control circuit. It is important to design circuits and choose components carefully to avoid contact races.

Question 11

Referring to the information in Table 17-1 (above), what is the maximum number of internal relays for this particular PLC?
A) 8
B) 16
C) 25
D) 75

Accepted Answer

The answer of  Referring to the information in Table...

Question 12

Control circuits are generally drawn as standard ____.
A) logic diagrams
B) lines of code
C) truth tables
D) schematic or ladder diagrams

Accepted Answer

Schematic or ladder diagrams are the standard way of drawing control circuits. Logic diagrams and truth tables are also used in the design of control circuits, but schematic or ladder diagrams are the most commonly used. Lines of code are not a type of diagram used in control circuits, although they may be used to program the behavior of a control circuit in a microcontroller or PLC.

Question 13

In a circuit designed to operate two well pumps, what is the protection mechanism?
A) fuse
B) circuit breaker
C) ground-fault protector
D) branch-circuit protector

Accepted Answer

The answer of In a circuit designed to operate two...

Question 14

The simplest way to convert a ladder diagram into a ____ is to make the changes in stages.
A) logic circuit
B) terminal diagram
C) schematic
D) coil diagram

Accepted Answer

Converting a ladder diagram into a logic circuit involves replacing the symbols and components with their corresponding logic gates and connections. This process can be done in stages by first identifying and replacing basic symbols such as contacts and coils, and gradually working up to more complex elements such as timers and counters. The other options, terminal diagrams, schematics, and coil diagrams, are not commonly used for converting ladder diagrams into other forms.

Question 15

What rules should be followed when converting a schematic?

Accepted Answer

The answer of What rules should be followed when converting...

Question 16

The water pump circuit will cause the pumps to alternate running each time the ____ switch closes.
A) limit
B) pressure
C) float
D) temperature

Accepted Answer

The answer of The water pump circuit will cause the...

Question 17

How are the inputs assigned in the PLC described in this chapter?

Accepted Answer

The answer of How are the inputs assigned in the...

Question 18

One advantage of PLCs is that any input can be assigned ____ contact(s).
A) one
B) 10
C) 1000
D) any number of

Accepted Answer

One advantage of PLCs is their flexibility in programming. Any input can be assigned any number of contacts, allowing for complex and customized control sequences. This makes PLCs a versatile option for a wide range of industrial automation applications.

Question 19

The second step in actualizing a ladder diagram is to add the logic that ____.
A) controls the pump one bypass circuit
B) controls motor starter coil 2M
C) controls motor starter coil 1M
D) controls the pump two bypass circuit

Accepted Answer

The answer of The second step in actualizing a ladder...

Question 20

Before a program can be developed from a ladder diagram, it is first necessary to determine the number of ____.
A) differential amplifiers
B) protection schemes
C) input and output devices
D) CPUs

Accepted Answer

Ladder diagrams represent a graphical description of a control circuit and as such, the input and output devices must be determined first in order to create the program. The other options, such as differential amplifiers, protection schemes or CPUs, might be necessary depending on the specific application, but they are not the primary consideration for developing a ladder diagram.

Quiz 17: Developing a Program for a Plc

How are the overload contacts connected in the logic circuit described in this chapter?

How is the operation of motor start coil 1M controlled in the example presented in this chapter?

When power is applied to an input, it will cause the contact assigned to that input to ____.

A PLC assumes inputs to be ____ when a program is loaded into memory.

The ____ input terminal is connected to the neutral or grounded power conductor.

Describe the circuit considered in this chapter.

In a logic diagram, each line of logic must end with a ____.

Given that the internal clock that controls the operation of timers operates in 0.1-second intervals, what value do you have to program in order to get a one-second delay from the timer?

A selector switch can be set to any of ____ operating modes.

A(n) ____ occurs when it is possible for one contact to open before another closes or for one contact to close before another opens.

Referring to the information in Table 17-1 (above) , what is the maximum number of internal relays for this particular PLC?

Control circuits are generally drawn as standard ____.

In a circuit designed to operate two well pumps, what is the protection mechanism?

The simplest way to convert a ladder diagram into a ____ is to make the changes in stages.

What rules should be followed when converting a schematic?

The water pump circuit will cause the pumps to alternate running each time the ____ switch closes.

How are the inputs assigned in the PLC described in this chapter?

One advantage of PLCs is that any input can be assigned ____ contact(s) .

The second step in actualizing a ladder diagram is to add the logic that ____.

Before a program can be developed from a ladder diagram, it is first necessary to determine the number of ____.