- •9.7.2 More Timers And Counters
- •9.7.3 Deadman Switch
- •9.7.4 Conveyor
- •9.7.5 Accept/Reject Sorting
- •9.7.6 Shear Press
- •9.8 SUMMARY
- •9.9 PRACTICE PROBLEMS
- •9.10 PRACTICE PROBLEM SOLUTIONS
- •9.11 ASSIGNMENT PROBLEMS
- •10. STRUCTURED LOGIC DESIGN
- •10.1 INTRODUCTION
- •10.2 PROCESS SEQUENCE BITS
- •10.3 TIMING DIAGRAMS
- •10.4 DESIGN CASES
- •10.5 SUMMARY
- •10.6 PRACTICE PROBLEMS
- •10.7 PRACTICE PROBLEM SOLUTIONS
- •10.8 ASSIGNMENT PROBLEMS
- •11. FLOWCHART BASED DESIGN
- •11.1 INTRODUCTION
- •11.2 BLOCK LOGIC
- •11.3 SEQUENCE BITS
- •11.4 SUMMARY
- •11.5 PRACTICE PROBLEMS
- •11.6 PRACTICE PROBLEM SOLUTIONS
- •11.7 ASSIGNMENT PROBLEMS
- •12. STATE BASED DESIGN
- •12.1 INTRODUCTION
- •12.1.1 State Diagram Example
- •12.1.2 Conversion to Ladder Logic
- •12.1.2.1 - Block Logic Conversion
- •12.1.2.2 - State Equations
- •12.1.2.3 - State-Transition Equations
- •12.2 SUMMARY
- •12.3 PRACTICE PROBLEMS
- •12.4 PRACTICE PROBLEM SOLUTIONS
- •12.5 ASSIGNMENT PROBLEMS
- •13. NUMBERS AND DATA
- •13.1 INTRODUCTION
- •13.2 NUMERICAL VALUES
- •13.2.1 Binary
- •13.2.1.1 - Boolean Operations
- •13.2.1.2 - Binary Mathematics
- •13.2.2 Other Base Number Systems
- •13.2.3 BCD (Binary Coded Decimal)
- •13.3 DATA CHARACTERIZATION
- •13.3.1 ASCII (American Standard Code for Information Interchange)
- •13.3.2 Parity
- •13.3.3 Checksums
- •13.3.4 Gray Code
- •13.4 SUMMARY
- •13.5 PRACTICE PROBLEMS
- •13.6 PRACTICE PROBLEM SOLUTIONS
- •13.7 ASSIGNMENT PROBLEMS
- •14. PLC MEMORY
- •14.1 INTRODUCTION
- •14.2 MEMORY ADDRESSES
- •14.3 PROGRAM FILES
- •14.4 DATA FILES
- •14.4.1 User Bit Memory
- •14.4.2 Timer Counter Memory
- •14.4.3 PLC Status Bits (for PLC-5s and Micrologix)
- •14.4.4 User Function Control Memory
- •14.4.5 Integer Memory
- •14.4.6 Floating Point Memory
- •14.5 SUMMARY
- •14.6 PRACTICE PROBLEMS
- •14.7 PRACTICE PROBLEM SOLUTIONS
- •14.8 ASSIGNMENT PROBLEMS
- •15. LADDER LOGIC FUNCTIONS
- •15.1 INTRODUCTION
- •15.2 DATA HANDLING
- •15.2.1 Move Functions
- •15.2.2 Mathematical Functions
- •15.2.3 Conversions
- •15.2.4 Array Data Functions
- •15.2.4.1 - Statistics
- •15.2.4.2 - Block Operations
- •15.3 LOGICAL FUNCTIONS
- •15.3.1 Comparison of Values
- •15.3.2 Boolean Functions
- •15.4 DESIGN CASES
- •15.4.1 Simple Calculation
- •15.4.2 For-Next
- •15.4.3 Series Calculation
- •15.4.4 Flashing Lights
- •15.5 SUMMARY
- •15.6 PRACTICE PROBLEMS
- •15.7 PRACTICE PROBLEM SOLUTIONS
- •15.8 ASSIGNMENT PROBLEMS
plc flowchart - 11.15
11.4SUMMARY
•Flowcharts are suited to processes with a single flow of execution.
•Flowcharts are suited to processes with clear sequences of operation.
11.5PRACTICE PROBLEMS
1. Convert the following flow chart to ladder logic. start
A on
yes
is B on? no
A off
no
is C on? yes
2.Draw a flow chart for cutting the grass, then develop ladder logic for three of the actions/decisions.
3.Design a garage door controller using a flowchart. The behavior of the garage door controller is as follows,
-there is a single button in the garage, and a single button remote control.
-when the button is pushed the door will move up or down.
-if the button is pushed once while moving, the door will stop, a second push will start motion again in the opposite direction.
-there are top/bottom limit switches to stop the motion of the door.
-there is a light beam across the bottom of the door. If the beam is cut while the door is closing the door will stop and reverse.
-there is a garage light that will be on for 5 minutes after the door opens or closes.
plc flowchart - 11.16
11.6 PRACTICE PROBLEM SOLUTIONS
1.
first scan |
|
L |
F1 |
U |
F2 |
U |
F3 |
U |
F4 |
F1 |
|
MCR |
|
L |
A |
U |
F1 |
L |
F2 |
MCR |
|
F2 |
|
MCR |
|
B |
|
U |
F2 |
L |
F3 |
MCR |
|
F3 |
|
MCR |
|
U |
A |
U |
F3 |
L |
F4 |
MCR |
|
start |
|
F1 |
A on |
|
|
||
F2 |
yes |
|
|
||
|
is B on? |
|
|
no |
|
F3 |
A off |
|
|
||
no |
F4 |
|
is C on? |
||
|
||
|
yes |
F4 |
|
MCR |
|
C |
|
U |
F4 |
L |
F1 |
C |
|
U |
F4 |
L |
F2 |
MCR |
plc flowchart - 11.17
2.
Start |
|
|
Get mower and |
F1 |
|
|
||
gas can |
|
|
F2 |
F3 |
|
yes |
||
Is gas can |
||
get gas |
||
empty? |
||
|
||
no |
|
|
F4 |
|
|
Fill mower |
|
|
F5 |
|
|
Pull cord |
|
|
F6 |
no |
|
Is Mower on? |
||
|
||
yes |
|
|
F7 |
|
|
Push Mower |
|
|
F8 |
no |
|
Is all lawn cut? |
|
|
yes |
|
|
F9 |
|
|
Stop mower |
|
|
F10 |
|
|
Put gas and |
|
|
mower away |
|
plc flowchart - 11.18
FS |
F1 |
|
|
|
F2 |
|
F3 |
|
F4 |
|
F5 |
|
F6 |
|
F7 |
|
F8 |
|
F9 |
|
F10 |
F1 |
|
MCR |
|
L |
mower |
L |
gas can |
U |
F1 |
L |
F2 |
MCR |
|
F2 |
|
MCR |
|
gas can empty |
F3 |
L |
|
U |
F2 |
gas can empty |
F4 |
L |
|
U |
F2 |
MCR |
plc flowchart - 11.19
F3 |
|
MCR |
|
gas can full |
fill gas tank |
|
|
L |
F4 |
U |
F3 |
MCR |
|
F4 |
|
MCR |
|
TON |
|
Timer T4:0 |
|
Delay 5s |
|
T4:0/DN |
F5 |
L |
|
U |
F4 |
T4:0/DN |
pour gas |
|
|
MCR |
|
F5 |
|
MCR |
|
cord pulled |
pull cord |
|
|
cord pulled |
|
L |
F6 |
U |
F5 |
MCR |
|
F6 |
|
MCR |
|
mower on |
|
L |
F7 |
mower on |
|
L |
F5 |
U |
F6 |
MCR |
ETC.....................
plc flowchart - 11.20
3.
start
ST1 |
is |
|
no |
|
|
remote or |
|
||||
|
button pushed? |
|
|
||
|
|
|
|||
ST2 |
|
yes |
|
|
|
|
|
|
|||
|
|
|
|
|
|
turn on door close |
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
is |
|
ST4 |
|
|
|
|
|
|
ST3 |
remote or |
no |
is |
yes |
|
button or bottom |
light beam |
||
|
limit pushed? |
|
on? |
|
|
|
|
|
yes |
no |
ST5
turn off door close
ST6 |
is |
|
|
|
||||
|
|
remote or |
|
|
|
|||
|
|
button pushed? |
|
|
|
|||
ST7 |
yes |
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
||
|
turn on door open |
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
is |
|
|
|
||
ST8 |
remote or |
no |
|
|
||||
|
|
button or top |
|
|
|
|||
|
|
limit pushed? |
|
|
|
|||
ST9 |
|
|
yes |
|
|
|
||
|
|
|
|
|
||||
|
|
|
|
|
|
|||
|
turn off door open |
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
first scan
ST2
ST7
T4:0/DN
plc flowchart - 11.21
L |
ST1 |
U |
ST2 |
U |
ST3 |
U |
ST4 |
U |
ST5 |
U |
ST6 |
U |
ST7 |
U |
ST8 |
U |
ST9 |
U |
door open |
U |
door close |
TOF
T4:0 preset 300s
garage light
plc flowchart - 11.22
ST1
button
remote
ST2
MCR
U ST1
ST2
L
MCR
MCR
U ST2
ST3
L
door close
L
MCR
plc flowchart - 11.23
ST3 |
|
|
MCR |
|
|
button |
|
|
U |
ST3 |
|
remote |
ST5 |
|
L |
||
|
||
bottom limit |
|
|
ST3 |
|
|
U |
ST3 |
|
L |
ST4 |
|
|
||
MCR |
|
|
ST4 |
|
|
MCR |
|
|
light beam |
|
|
U |
ST4 |
|
L |
ST7 |
|
|
||
light beam |
|
|
U |
ST4 |
|
L |
ST3 |
|
|
||
MCR |
|
plc flowchart - 11.24
ST5
ST6
button
remote
ST7
MCR
U ST5
ST6
L
door close
U
MCR
MCR
U ST6
ST7
L
MCR
MCR
U ST7
ST8
L
door open
L
MCR
plc flowchart - 11.25
ST8
button
remote
top limit
ST9
MCR
U ST8
ST9
L
MCR
MCR
U ST9
ST1
L
door open
U
MCR