3. Industrial Applications on Automation
When a plant is to be replaced by Automation
we have to consider
Why?
Accuracy
Productivity
Cost
Other
How?
User requirements
System requirements
What to use?
Select Sensors, actuators and
control methods
Many automation plant uses PLC
6. Component Based
automation
Component based automation (CBA), the decentralized
approach to automation with distributed intelligence in
technological modules, is picking up speed. Component
based automation clearly simplifies planning, engineering
and commissioning of complex plans and reduces the time
needed for the start of production by between 10% and 15%.
7. Planning your
automation
Main system requirements
Under this, the main requirement and functions
expected from the system has to be identified.
Outputs: Reports, UML based diagrams etc.
Component Selection
Design the system to match the main requirement
and fail safe design in terms of programming testing
as well as maintenance.
Industrial Survey could be very helpful
Outputs: Layout diagrams, component diagrams
8. Planning your
automation
Inclusion of monitoring and Control from higher levels
It should be identified the requirements of
monitoring and controlling from higher levels to
decide whether SCADA systems to be included or
not
Outputs: Report or UML format
Maintenance and Scheduling support
Preventive maintenance reminders, auto scheduling
requirements, historical records etc.
Outputs: Reports
9. PLC programming
Micro level Macro level
Macro-level Programming
Organizational Blocks
Programmable Blocks
Data blocks and Data words
10. Basics of designing a
program structure
The CPU run two programs
1. The operating system
2. User program
11. Operating Systems
Handling start
Update the process images
Calling user programs
Acquisition interrupt programs and calling
relevant OBs
Error handling
Memory Management
Communicating with other devices
12. User program
Specifying conditions to restart
Processing process data
Reactions to interrupt
Handling disturbances in the normal
program cycle
13. Block Types S7-300
Organization blocks
Functions (FC)
Function blocks (FB)
Data Blocks
System Function Blocks (SFB and
SFC)
14. Organization Blocks
Main organization Block (OB1)
Time of Day interrupts (OB10 to OB 17)
Time Delay interrupts (OB 20 to OB 23)
Cycle interrupts (OB 30 to OB 38)
Hardware interrupts (OB 40 to OB 47)
Start up (OB 100, OB 101 and OB 102)
15. Functions
A logic block without memory. Temp.
variables are stacked on a local area
and lost after leaving the block.
You can use data blocks to write
permanently.
16. Function Blocks
Program with memory. An instance
data block is created with the function
block.
By calling more than one IDB with one
FB you can get similar functions
working simultaneously.
17. Ex. Function Block (FB)
Formal parameter
Start INT IN
Speed INT IN
History DT IN_OUT
Run_time TIME IN_OUT
FB 20:Motor
Integer 16 Bits: Start
Integer 16 Bits: Speed
Data and Time : 48 bits
Time 32 bits: run time
Actual parameter
DB 202:Motor_2
18. FB Ex. Contd.
FB 21: Motor Processing
Variable declaration
Start Motor_1, FB 22
Start Motor_2, FB 22
Start Motor_3, FB 22
DB 100
Data for Motor_1
Data for Motor_2
Data for Motor_3
FB 22: Motors Call FB 21 from logic block
CALL FB 21,DB 100
Transfer data
CALL Motor_1
CALL Motor_2
CALL Motor_3
19. Data Blocks
FC 10
FC 11
FB 12
Shared DB
DB 20
(Access by all blocks
or any block)
Instance DB
DB 112
(access only by
FB 12)
20. SFC and SFB
They are in built functions and functions
Blocks that can be used.
21. Use of Word logic
L MW 30
L MW 28
OW
T MW 32
L MW 60
L MW 64
AW
T MW 10
L MW 16
L MW 12
XORW
T MW 40
22. Load
When an input, output or memory of a
byte, word or double word is loaded it
is stored in the accumulator
L MB 10
ACC2
ACC1 MB10
L MB 20
ACC1
ACC2 MB10
MB20
