PLC's Chapter 5

Question 1

Explain Rack-based memory

Answer 1

With rack-based memory structures addresses are derived using the rack number, the I/O module slot number and the screw terminal number where the I/O device is wired. 
With rack-based memory structures addresses are derived using the rack number, the I/O module slot number and the screw terminal number where the I/O device is wired.

Question 2

Explain Tag-based memory

Answer 2

With tag-based memory structures all data are assigned a variable name called a tag. A program can be developed using only tag names but you must assign input and output terminals to input and output tags before the program can be executed

Question 3

The memory space can be divided into two broad categories: ____ files and ____files.

Answer 3

The memory space can be divided into two broad categories:

program files and Data files.

Question 4

Program files are the ___ of processor _____ where ladder logic programming is _____.

Answer 4

Program files are the areas of processor memory where ladder logic programming is stored.

Question 5

Program files are the___of the _____ memory that stores the user ____logic program. The program accounts for most of the ____memory of a given PLC system.

Answer 5

Program files are the part of the processor memory that stores the user ladder logic program. The program accounts for most of the total memory of a given PLC system.

Question 6

The Data file _____ of the processor’s______stores ____and ____status, processor status, the status of various bits, and numerical data.

Answer 6

The Data file portion of the processor’s memory stores input and output status, processor status, the status of various bits, and numerical data.

Question 7

The PLC-5 and SLC 500 ____all ____ in global data _____ and are based on __-bit operations.

Answer 7

The PLC-5 and SLC 500 store all data in global data tables and are based on 16-bit operations.

Question 8

You ____these ____by specifying the _______of the data you want.

Answer 8

You access these data by specifying the address of the data you want.

Question 9

The _______ in the ____data file and the ____

____ for I/O modules mounted in the chassis.

Answer 9

The addresses in the output data file and the input

data file are potential locations for I/O modules mounted in the chassis.

Question 10

The ____data file ____information about the _____ status.

Answer 10

The status data file contains information about the processor status.

Question 11

The_____________ stores bit status and ___________ serves for _______when using internal outputs.

Answer 11

The bit data file stores bit status and frequently serves for storage when using internal outputs.

Question 12

The_____ file____ the timer ____ and timer data.

Answer 12

The timer file stores the timer status and timer data.

Question 13

The_____file ____ the ______status and _____

data.

Answer 13

The counter file stores the counter status and counter

data.

Question 14

The ____image table is allocated to _____the on/off status of connected discrete inputs.

Answer 14

The input image table is allocated to storing the on/off status of connected discrete inputs.

Question 15

If the input is on (switch closed), its corresponding

bit in the table is set to__.

Answer 15

If the input is on (switch closed), its corresponding

bit in the table is set to 1.

Question 16

If the input is off (switch open), the corresponding

bit is cleared, or reset to __.

Answer 16

If the input is off (switch open), the corresponding

bit is cleared, or reset to 0.

Question 17

The ________table is allocated to _____ the on/off status of connected discrete outputs.

Answer 17

The output image table is allocated to storing the on/off status of connected discrete outputs.

Question 18

If the program calls for an output to be ON, its corresponding bit in the table is set to ____.

Answer 18

If the program calls for an output to be ON, its corresponding bit in the table is set to 1.

Question 19

If the program calls for an output to be OFF, its corresponding bit in the table is set to __.

Answer 19

If the program calls for an output to be OFF, its corresponding bit in the table is set to __.

Question 20

Simulated operation of the _________ table _____status of connected discrete outputs.

Answer 20

Simulated operation of the output image table on/off status of connected discrete outputs.

Question 21

Typically,____PLCs have a ____ number of _____ and ______.

Answer 21

Typically, micro PLCs have a fixed number of inputs and outputs.

Question 22

During ____ program scan cycle, the processor reads all the ____, takes these _____, and _______ or _______ the _____ according to the user program.

Answer 22

During each program scan cycle, the processor

reads all the inputs, takes these values, and energizes or de-energizes the outputs according to the user program.

Question 23

The___ it takes to ____ a scan cycle is a measure of how___the controller can _____ to changes in inputs.

Answer 23

The time it takes to complete a scan cycle is a measure of how fast the controller can react to changes in inputs.

Question 24

The scan time is a function of:
• The speed of the processor module
• The length of the ladder program
• The type of instructions executed
• The actual ladder true/false conditions

Answer 24

The scan time is a function of:
• The speed of the processor module
• The length of the ladder program
• The type of instructions executed
• The actual ladder true/false conditions