PLC Quiz 2
Usually a group of 8 bits is a byte, and a group of one or more bytes is a word.
True
A OR gate operates on the same principle as:
a parallel circuit.
The logic function(s) used by PI-Cs is (are):
all of these
The number 127 could not be:
binary
The basic rule for an OR gate is:
if one or more inputs are 1, the output is 1.
The ASCII code:
includes letters as well as numbers.
A single rung of a ladder logic program is arranged with:
input conditions connected from left to right, with the output at the far right.
In the sign bit position, a 1 indicates a(n):
negative number.
The octal number 153 would be written in binary as:
001 101 011.
The decimal number 213 would be written in BCD as:
0010 0001 0011.
The hexadecimal number 2D9 would be written in binary as:
0010 1101 1001
The 2's complement form of a binary number is the binary number that results when:
1 is added to the 1's complement.
The decimal system has as its base:
10
The truth table for the logic symbol is:
1110
The decimal number 28 would be written in binary as:
11100.
The decimal number 15 would be written in binary as:
1111
The number 12 is:
12 in decimal
The hexadecimal number C4 would be written in decimal as:
196
If a given memory unit consists of 1250 16-bit words, the memory capacity would be rated:
20,000 bits.
The binary number 101101 would be written in decimal as:
45
The binary number 101 has the decimal equivalent of:
5
The octal number 62 would be written in decimal as:
50
For a base 8 number system, the weight value associated with the third digit would be:
64
Which of the following number systems has a base of 16?
Hexadecimal
There is no difference between a relay schematic and a ladder logic program.
False
If you want to know when one or both matching bits in two different words are ON, you would use the logic instruction.
OR
The acronym BCD stands for:
binary-coded decimal.
The binary concept makes use of the fact that certain informal
can exist in one of two possible states.
A NOT function is used when a logic 1 must some device.
deactivate
All digital computing devices operate using the binary number system because:
digital circuits can be easily distinguished between two voltage levels
The basic rule for an AND gate is:
if all inputs are 1, the output will be 1.
The basic rule for an XOR function is:
if one or more inputs are 0, the output is 1.
A gate is a device that:
performs a logical decision based on its inputs.
In any number system, the position of a digit that represents part of the number has a "weight" associated with its value. The place weights for binary:
start with 1 and are successive powers of 2
An AND gate operates on the same principle as:
a series circuit.
In conventional logic circuits, binary 1 represents:
all of these
The NOT function can be thought of as:
all of these
A NOR gate is:
an OR gate with an inverter connected to the output.
All digital computing devices perform operations in binary.
True
All inputs to an AND gate must be 1 to produce a 1 output.
True
Hardwired logic can be implemented using relays and relay schematics
True
Hardwired logic is fixed and is changeable only by altering the way devices are connected.
True
Hardwired logic refers to logic control functions determined by the way devices are interconnected.
True
In any number system, the position of a digit that represents part of the number has a weighted value associated with it.
True
In the Gray code there is a maximum of one bit change between two consecutive numbers.
True
Inverting the output of an OR gate will result in creating a NOR gate.
True
Ladder logic is a graphical representation of a user program.
True
Normally, a binary 1 represents the presence of a signal, while a binary 0 represents the absence of a signal.
True
On some PLCs, only one output is allowed per ladder logic rung.
True
One of the most common PLC programming languages is ladder logic.
True
Only one input to an OR gate must be 1 to produce a 1 output.
True
Programmable control is based on logic functions that are programmable and easily changed.
True
The base of a number system determines the total number of unique symbols used by that system.
True
The hexadecimal number system consists of 16 digits including the numbers 0 through 9 and letters A through F.
True
The octal number system consists of digits 0, 1, 2, 3, 4, 5, 6, and 7. There are no 8's or 9's.
True
The radix of a number system is the same as the base.
True
A two input OR function, expressed as a Boolean equation, would be Y= AB.
False
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.
False
All inputs to a NAND gate must be 1 to produce a 1 output.
False
All inputs to a NOR gate must be 1 to produce a 1 output.
False
Binary number systems use positive and negative symbols to represent the polarity of a number.
False
The AND function, implemented using switches, will mean switches connected in parallel.
False
The decimal system uses the number 9 as its base.
False
To express a number in binary requires fewer digits than in the decimal system.
False
The main advantage of using the Gray code is:
only one digit changes as the number increases.
The OR function, implemented using contacts, requires contacts connected in:
parallel
A(n) bit is used to detect errors that may occur while a word is moved.
parity
