Deck 4: Fundamentals of Logic

Question 1

Hardwired logic is fixed and is changeable only by altering the way devices are connected.

Answer 1

True

Question 2

Hardwired logic refers to logic control functions determined by the way devices are interconnected.

Answer 2

True

Question 3

Inverting the output of an OR gate will result in creating a NOR gate.

Answer 3

True

Question 4

There is no difference between a relay schematic and a ladder logic program.

Question 5

Hardwired logic can be implemented using relays and relay schematics.

Question 6

Programmable control is based on logic functions that are programmable and easily changed.

Question 7

On some PLCs,only one output is allowed per ladder logic rung.

Question 8

All gates are devices that have one input with which they perform logic decisions and produce a result at one or more of their outputs.

Question 9

The binary concept makes use of the fact that certain informal:

A)can exist in one of two possible states.
B)can be broken down into smaller units for easier analysis.
C)can be divided into two or more categories.
D)can be divided into two,or multiples of two,categories.

Question 10

Ladder logic is a graphical representation of a user program.

Question 11

A two input OR function,expressed as a Boolean equation,would be Y= AB.

Question 12

Normally,a binary 1 represents the presence of a signal,while a binary 0 represents the absence of a signal.

Question 13

A gate is a device that:

A)allows current flow in one direction only.
B)changes alternating current to direct current.
C)performs a logical decision based on its inputs.
D)performs a logical decision based on its outputs.

Question 14

One of the most common PLC programming languages is ladder logic.

Question 15

Only one input to an OR gate must be 1 to produce a 1 output.

Question 16

All inputs to an AND gate must be 1 to produce a 1 output.

Question 17

The AND function,implemented using switches,will mean switches connected in parallel.

Question 18

All inputs to a NAND gate must be 1 to produce a 1 output.

Question 19

In conventional logic circuits,binary 1 represents:

A)the presence of a signal.
B)the occurrence of some event.
C)a high voltage level.
D)all of these.

Question 20

All inputs to a NOR gate must be 1 to produce a 1 output.

Question 21

The basic rule for an OR gate is:

A)if one or more inputs are 1,the output is 1.
B)if one or more inputs are 1,output is 0.
C)if one or more inputs are 0,the output is 1.
D)both b and c.

Question 22

The basic rule for an AND gate is:

A)if all inputs are 1,the output will be 1.
B)if all inputs are 1,the output will be 0.
C)if all inputs are 0,the output will be 1.
D)both a and b.

Question 23

The logic symbol drawn is that of the:

A)AND function.
B)OR function.
C)NOR function.
D)NAND function.

Question 24

The logic function(s)used by PI-Cs is (are):

A)AND
B)OR
C)NOT
D)all of these.

Question 25

The Boolean expression for the logic circuit drawn is:

A)Y = (A B)(CD)
B)
C)
D)Y= ABC + D

Question 26

The Boolean expression for the logic circuit is:

A)
B)
C)
D)

Question 27

Which logic circuit represents the Boolean expression

A)(a)
B)(b)
C)(c)
D)(d)

Question 28

Which logic circuit represents the Boolean expression Y = A(BC+D)?

A)(a)
B)(b)
C)(c)
D)(d)

Question 29

The Boolean expression for the logic circuit drawn is:

A)Y = ABC
B)Y=A+B+C
C)Y = (A + B)C
D)Y=AB+C

Question 30

The logic symbol drawn is that of the:

A)NOT function.
B)NOR function.
C)NAND function.
D)OR function.

Question 31

The Boolean equation for the logic symbol is:

A)A = Y
B)A=B
C)
D)

Question 32

The truth table for the logic symbol is:

A)(a)
B)(b)
C)(c)
D)(d)

Question 33

The logic symbol drawn is that of the:

A)AND function.
B)OR function.
C)NOT function.
D)NOR function.

Question 34

A NOT function is used when a logic 1 must ________ some device.

A)activate
B)deactivate
C)switch
D)light

Question 35

The NOT function can be thought of as:

A)a FALSE-to-TRUE converter.
B)a changer of states.
C)an inverter.
D)all of these.

Question 36

The Boolean equation for the logic symbol is:

A)Y= A + B
B)Y= AB
C)Y= A $\bullet$ B
D)either b or c.

Question 37

The Boolean equation for the logic symbol is:

A)Y= A+B+C
B)Y = ABC
C)Y= (AB)+C
D)Y = (A -B)C

Question 38

The OR function,implemented using contacts,requires contacts connected in:

A)series
B)parallel
C)series/parallel
D)parallel/series

Question 39

The logic symbol shown is that of the:

A)AND function.
B)OR function.
C)NOT function.
D)NAND function.

Question 40

With reference to the logic circuit,the output Y will be at a logic 1 when:

A)inputs A and B are logic 1.
B)input A or B is logic 1.
C)input A is at logic 1 and input B is at logic 0.
D)input A is at logic 0 and input B is at logic 1.

Question 41

A single rung of a ladder logic program is arranged with:

A)input conditions connected from left to right,with the output at the far right.
B)input conditions connected from right to left,with the output at the far left.
C)the output in the center and the input conditions to the left and right of it.
D)all input conditions in parallel and all output conditions in series.

Question 42

If you want to know when one or both matching bits in two different words are ON,you would use the logic instruction.

A)AND
B)XOR
C)OR
D)NOT

Question 43

The Boolean expression for the logic circuit drawn is:

A)
B)
C)
D)

Question 44

The basic rule for an XOR function is:

A)if one or the other,but not both,inputs are 1,the output is 1.
B)if one or more inputs are 1,the output is 1.
C)if one or more inputs are 1,the output is 0.
D)if one or more inputs are 0,the output is 1.

Question 45

A NOR gate is:

A)an AND gate with an inverter connected to the output.
B)an OR gate with an inverter connected to the output.
C)equivalent to a series circuit.
D)equivalent to a parallel circuit.

Question 46

An AND gate operates on the same principle as:

A)a series circuit.
B)a parallel circuit.
C)a series-parallel circuit.
D)none of these.

Question 47

An OR gate operates on the same principle as:

A)a series circuit.
B)a parallel circuit.
C)a series-parallel circuit.
D)none of these.

Question 48

Which of the hardwired relay schematics is being implemented by the PLC program shown?

A)(a)
B)(b)
C)(c)
D)(d)