PLC'S Chapters 1&2

Question 1

The number and type of I/Os cannot be changed in a fixed PLC.

Answer 1

True

Question 2

In a PLC system, there is a physical connection between field inputs devices and output devices.

Answer 2

False

Question 3

The input/output system forms the interfaces through which field devices are connected to the controller.

Answer 3

True

Question 4

A PLC is basically a computer designed for use in electrical control applications.

Answer 4

True

Question 5

Removing the programming device from the PLC will not affect the operation of the user program.

Answer 5

True

Question 6

When dealing with PLC memory, one K of memory represents 1024.

Answer 6

True

Question 7

The number of I/O points does not affect the memory size required for a PLC installation.

Answer 7

True

Question 8

Modifying relay-type process control circuits usually involves changing the:
A. Circuit wiring
B. Input circuit modules
C. Output circuit modules
D. Circuit operating voltage levels

Answer 8

A

Question 9

The control plan stored in the PLC is called:
A. A Program
B. A Boolean ladder
C. FORTRAN
D. A microprocessor

Answer 9

A

Question 10

When a field device contact connected to the input module closes:
A. A logic 1 is recorded in the memory location of the coil with the same address.
B. A logic 1 is recorded in the memory location of the contact with the same address
C.A logic 0 is recorded in the memory location of the contact with the same address
D.A logic 1 is recorded in the memory location of the contact with the same address.

Answer 10

D

Question 11

The scan time is the time required:
A. To record the status of all input devices.
B. To record the status of all output devices.
C. To execute one cycle of the total program.
D. For the information to pass from input to output

Answer 11

C

Question 12

Block No.4 of the PLC block diagram represents the:

A. Memory
B. Programming device
C. Input module
D. CPU

Answer 12

C

Question 13

Which module of the PLC connects directly to fiel devices such as pilot lights, motor starters, and solenoids.
A. Input
B. Output
C. Power supply
D. Memory

Answer 13

B

Question 14

PLC software that runs on a personal computer can be used to:
A. Write a PLC program
B. Document a PLC program
C. Monitor the control process
D. All the above

Answer 14

D

Question 15

I/O modules are designed to plug into a slot or connector.

Answer 15

True

Question 16

The processor may perform functions such as timing, counting, and comparing in addition to logic processing.

Answer 16

True

Question 17

Memory is where the control plan is held or stored in the controller.

Answer 17

True

Question 18

When a new program is loaded into a PLC’s memory, the old program that was stored in the same location is over-written and essentially erased.

Answer 18

True

Question 19

Most PLC programming software will allow you to develop programs on another manufacturer’s PLC.

Answer 19

False

Question 20

Analog signals can have only two states.

Answer 20

False

Question 21

Discrete means that each input or output has two states: turn (on) or false (off).

Answer 21

True

Question 22

Digital modules are also called discrete modules.

Answer 22

True

Question 23

An analog input or output is a signal that varies continuously within a certain range.

Answer 23

True

Question 24

Optical isolation used in I/O modules helps to reduce the effects of electrical noise.

Answer 24

True

Question 25

``` A ___ is an example of a device that be controlled by a discrete output from a PLC. A. Pushbutton B. Motor starter C. Limit switch D. All of these ```

Answer 25

B

Question 26

``` One function of a PLC input interface module is to: A. Accept signals from field devices and convert them into signals that can be used by the processor. B. Convert signals from the processing unit into values that can be used to control the machine or process. C. Input signals from the programming device and convert them into signals that can be used by the CPU. D. Interpret and execute the user program that controls the machine or process ```

Answer 26

A

Question 27

A discrete output interface module is designed to provide: ``` A. Output voltages only in the 5 VDC range. B. Varying AC or DC voltages depending on the type of module selected. C.ON/OFF switching of the output field device. D. Binary-coded outputs. ```

Answer 27

C

Question 28

The following statement that does not apply to the optical isolator circuit used in I/O modules is that it: A. Separates high voltage and low voltage circuits. B. Rectifies AC signals C. Prevents damage caused by line voltage transients. D. Reduces the effect of electrical noise.

Answer 28

B

Question 29

``` Which of the following is not a function of a PLC programming device? A. To enter the user program B. To change the user program C. To execute the user program D. To monitor the user program ```

Answer 29

C

Question 30

``` The I/O system provides an interface between: A. Input modules and output modules. B. The CPU and field equipment. C. The CPU and I/O rack. D. The I/O rack and I/O modules. ```

Answer 30

B

Question 31

``` The Allen-Bradly SLC-500 address I:2/4 refers to an: A. Input module in slot 4, terminal 2. B. Output module in slot 4, terminal 2 C. Input module in slot 2, terminal 4 D. Output module in slot 2, terminal 4 ```

Answer 31

C

Question 32

``` The Allen-Bradly SLC-500 address O:3/0 refers to an: A. Input module in slot 3, terminal 0. B. Output module in slot 3, terminal 0 C. Input module in slot 0, terminal 3 D. Output module in slot 0, terminal ```

Answer 32

B