3. TARGET TO
CONTROL SYS.
Automatic Controller
WHAT
Origin of PLC
History
Sizes of PLC’s
Cycle of Operation
Which
APPLICATIONS N REAL
PLC H.W Components:
INPUT TO PLC ,SENSING CONCEPTS
9. Batch Process
has a beginning and an end “complete
product control process” , Some
applications require that specific quantities
of raw materials be combined in specific
ways for particular durations to produce
an intermediate or end result.
Example:
production of food and medicine.
10. Continuous Process
Often, a physical system is represented though
variables that are smooth and uninterrupted in
time.
Example :control of the water temperature in a
heating jacket,
11. Discrete
It is Not independent, Most discrete
manufacturing involves the production of
discrete pieces of product
Examples :
metal stamping.
automotive production.
12. Hybrid
Applications having elements of
discrete, batch and continuous process
control are often called hybrid
applications.
13. Sequential Control
Control a process that is a series of tasks to be
performed (sequence of operation ),each task
is performed under :-
Time driven . Common in open loop sys
Event driven . Common in closed loop sys
Example washing machine
In PLC the SFC is powerful Lang for it .
14. Motion Control
Controlling motion in electromechanical sys
Rotational or Linear by Servomotor.
Digital by NC (Numerical Control).
3 dimension by Robotic.
16. µC
DCS PC
Mr.
CNC CONTROLLER
PLC
SCADA PAC
FPGA
17. Automatic controllers
µC==Microcontroller.
FPGA not FBGA.
PC
Mr. PLC
DCS== Distributed Control System
SCADA == Supervisory Control And Data Acquisition
CNC == Computer Numerical Control
PAC ==Programmable Automation Controller
21. WHAT
Programmable logic controllers, also called
programmable controllers or PLCs, are
solid-state members of the computer
family, using integrated circuits instead of
electromechanical devices to implement
control functions.
They are capable of storing
instructions, such as
sequencing, timing, counting, arithmetic, dat
a manipulation, and communication, to
control industrial machines and processes
24. Microprocessor
The block that will have a built in
capability to Add “multiply, divide,
subtract”, and move its contents from
one memory location onto another is
called "central processing unit" (CPU).
25. Characteristics differentiate
microprocessors
Instruction set The set of instructions that
the microprocessor can execute
bandwidth The number of bits processed
in a single instruction
clock speed Given in megahertz MHz
the clock speed determines how many
instructions per second the processor can
execute
26. Microcontroller
A microcontroller (also MCU or µC) is a
functional computer system-on-a-chip.
It contains a processor core, memory, and
programmable input/output peripherals.
31. History of PLCs
The first Programmable Logic Controllers were
designed and developed by Modicon as a relay
replacer for GM and Landis
The first PLC, model 084, was invented by Dick
Morley in 1969
The first commercial successful PLC, the 184, was
designed by Michael Greenberg in 1973
44. Sequence of PLC control
When a process is controlled by a PLC it
uses inputs from sensors to make
decisions and update outputs to drive
actuators
The process is a real process that will
change over time. Actuators will drive the
system to new states (or modes of
operation). This means that the controller is
limited by the sensors available, if an input
is not available, the controller will have no
way to detect a condition “real time
system “.
46. Number Of
Scan Special I/O
Time Modules
Memory Communications
Software
Number Of
Availability
Logical I/O
Select
PLC Peripherals
Type Of
Controller
60. PLC H.W Components:
CPU =ALU +CU
System Busses
Memory
I/O Sections
Power Supply Unit
Programming Device
61. Programming Device
The programming device is used to enter
the required program into the memory of
the processor.
The program is DEVELOPED in the
programming device and then
TRANSFERRED TO MEMORY unit of
the PLC.
62. CPU
Microprocessor based, allow arithmetic
operations, logic operators, block memory
moves, computer interface ,and local area
network, functions,.. etc.
CPU makes a great number of CHECK-UPS of the
PLC controller itself so eventual errors would be
discovered early.
This is an intro to a point in next session
63. I/O Sections
Inputs monitor field devices, such as
switches and sensors.
Outputs control other devices, such as
motors, pumps, solenoid valves, and
lights.
64. Power Supply Unit
Most PLC controllers work either at 24
VDC or 220 VAC.
Some PLC controllers have electrical
supply as a separate module, while
small and medium series already
contain the supply module.
Max current is 10mA.
65. Memory
System (ROM) to give permanent storage
for the operating system and the fixed
data used by the CPU.RAM for data.
This is where information is stored on
the status of input and output devices
and the values of timers and counters
and other internal devices. EPROM for
ROM’s that can be programmed and
then the program made permanent.
68. System Busses
The internal paths along which the digital
signals flow within the PLC are called
busses.
The system has four busses:
The CPU uses the DATA BUS for sending data
between the different elements,
The ADDRESS BUS to send the addresses of
locations for accessing stored data,
The CONTROL BUS for signals relating to
internal control actions,
The SYSTEM BUS is used for communications
between the I/O ports and the I/O unit.
76. Sensors
Feed back elements which convert the
physical quantity into electrical signals
Now we introduce some sensors as
refreshment ,Let me go ahead ☺
77. Useful Rule
If
U can measure it ,
U can control it
Obama say if the sun light is can measure it and emamof say this is the 1st exception is provide the truth of
the rule
87. $5 Moire Fringes
These are used in high precision applications
over long distances, often meters.
They can be purchased from a number of
suppliers, but the cost will be high. Typical
applications include Coordinate Measuring
Machines (CMMs).
90. 6- Chemical pH
The pH of an ionic fluid can be measured
over the range from a strong base
(alkaline) with pH=14, to a neutral value,
pH=7, to a strong acid, pH=0. These
measurements are normally made with
electrodes that are in direct contact with
the fluids.
control systems may classify to open or closed loop, analog or digital. Yet we can classify control systems in other ways, which have to do with applications to. Process control Sequential control Motion control
FPGA==can prog by VHDL or VerilogClosed sys contain sensorz
PAC ==describes this new generation of industrial controllers that combines the functionality of a PLC and a PC.As the technological differences between PC and PLC wane, a new class of controllers is emerging for engineers who require higher loop rates, advanced control algorithms, more analog capabilities, and better integration with the enterprise network. The Programmable Automation Controller (PAC) describes this new generation of industrial controllers that combines the functionality of a PLC and a PC.
Open Frame PLC(Triangle Research Inc., Pte. Ltd.)single printed circuit board as shown in Figure 2-1.They are sometimes called single board PLCs or open frame PLCs. These are totallyself contained (with the exception of a power supply) and, when installed in a system, theyare simply mounted inside a controls cabinet on threaded standoffs. Screw terminals onthe printed circuit board allow for the connection of the input, output, and power supplywires. These units are generally not expandable, meaning that extra inputs, outputs, andmemory cannot be added to the basic unit. However, some of the more sophisticatedmodels can be linked by cable to expansion boards that can provide extra I/O. Therefore,with few exceptions, when using this type of PLC, the system designer must take care tospecify a unit that has enough inputs, outputs, and programming capability to handle boththe present need of the system and any future modifications that may be required. Singleboard PLCs are very inexpensive (some less than $100), easy to program, small, andconsume little power, but, generally speaking, they do not have a large number of inputsand outputs, and have a somewhat limited instruction set. They are best suited to small,relatively simple control applications.
(Omron Electronics) Modularized PLC
usually based upon the required inputs, outputs and functions of the controller. The first decision is the type of controller; rack, mini, micro, or software based. This decision will depend on After the planning phase of the design, the equipment can be ordered. This deci-sion is usually based upon the required inputs, outputs and functions of the controller. The first decision is the type of controller; rack, mini, micro, or software based. This decision will depend upon the basic criteria listed below.• Number of logical inputs and outputs.• Memory - Often 1K and up. Need is dictated by size of ladder logic program. A ladder element will take only a few bytes, and will be specified in manufactur-ers documentation.• Number of special I/O modules - When doing some exotic applications, a large number of special add-on cards may be required.• Scan Time - Big programs or faster processes will require shorter scan times. And, the shorter the scan time, the higher the cost. Typical values for this are 1 microsecond per simple ladder instruction• Communications - Serial and networked connections allow the PLC to be pro-grammed and talk to other PLCs. The needs are determined by the application.• Software - Availability of programming software and other tools determines the programming and debugging ease.The process of selecting a PLC can be broken into the steps listed below.1. Understand the process to be controlled (Note: This is done using the design sheets in the previous chapter).• List the number and types of inputs and outputs.• Determine how the process is to be controlled.
Tissue Packing Machine
ammonia and ethylene processing
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This is an intro to a point in next session Errors fatal or non
Von Neumann architecture memory “memory-mapped I/O “accesses hardware by reading and writing to specific memory locations, using the same assembler language instructions that computer would normally use to access memory.
Is a device used to detect the presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are used extensively in industrial manufacturing. There are three different functional types, opposed, retro reflective, and proximity-sensing.