technical presentation on
TRANSCRIPT
PLC - PRIYA SRIVASTAVA
090105801
Automation is a step beyond
mechanization.
Automation is the use of control
systems & information
technologies to reduce the need
for human work in the production of goods & services.
AUTOMATION
Automation Components
Sensor for sensing physical
conditions
TransmittersControl Systems
Output Devices
AUTOMATION: TYPICAL INSTALLATION
Sensors placed in the field
Junction Box
Control Hardware
SCADA Software
Field Cabling
COMMUNICATION CABLE
Automation : Typical installation .
PLC’s History:
• Developed to replace relays in the late 1960s.
• PLC began in the 1970s, and has become the most common choice for manufacturing controls.
• The PLC was invented in response to the needs of the American automotive manufacturing industry (primarily General motors).
• Costs dropped and became popular by 1980s.
• Now used in many industrial designs.
Programmable Logic Controllers
A PLC is a solid state / industrial
computer that performs discrete or sequential
logic in a factory environment.
It was originally developed to
replace mechanical relays, timers, counters.
A sequence of instructions is
programmed by the user to the PLC memory. Its purpose is to monitor
crucial process parameters and adjust process
operations accordingly.
It performs functions
as:
On/Off
Control
Timing
Counting
Arithmetic
PLC Saves
Material cost
Installation cost
Troubleshooting
Labor cost
Value added benefits
Reliability
Flexibility
Advanced Function Communication
Speed
Diagnostics
ByReduced wiring &
associated errors
Less spaceNo moving
parts – rugged
ADVANTAGES
Advantages of PLC’s:
-Reliable in operation.-Flexibility in programming and
reprogramming in the plant.-Online/offline modifications.-Cost effective for controlling complex
systems.-Small physical size, shorter project
time.-Speed of operation.-Ability to communicate with
computer systems in the plant.-Ease of maintenance
/troubleshooting. -Documentation.-Security.
Disadvantages of PLC’s:
Most PLCs manufacturers offer on closed
architectures for their
products .
PLC devices are proprietary
which limit the
design and cost options.
Packaging
Material Handling
Power Generation
Security Systems
Paint Lines
Bottling & Canning
Machining
Automated assembly
Water treatments
HVAC/Building Automation
Industry
Cement
Automobile
Chemicals
Plastics
Any application in any industry that requires electrical control.
APLLICATIONS
Various Brands of PLCs
Allen Bradley( USA)
Siemens (Germany)
Modicon (France)
Mitshubishi (Japan)
GE Fanuc (USA)
Programming Languages
Ladder Diagram (LD)
Functional block Diagram (FBD)
Structured Text (ST)
Instruction List (IL)
Sequential Functional Chart
(SFC)
Programming languages used to program a PLC.
• Ladder logic is the most commonly used PLC programming language.
• Ladder logic programming has been expanded to include such functions as counters, timers ,shift registers and math operations.
LADDER DIAGRAM:
. Symbols for PLC programming:
Normally Open Pushbutton
Normally Closed Pushbutton
Normally Open switch
Normally Closed switch
Normally Open contact
Normally closed contact
OPERATIONS
Each rung or network on a ladder program represents a logic operation. In the rung above, both inputs A and B must be true (1) in order for the output C to be true (1).
A B C
PLC PROGRAMMING SOFTWARE
COMPONENTS OF PLC
A. Processor.
B. Memory unit.
C. Power supply.
D. Input/Output Modules.
E. Programming device.
Major Components of a Common PLC
19
PROCESSOR
POWERSUPPLY
I MN O P D U UT L E
O M U OT DP UU LT E
PROGRAMMING DEVICE
From SENSORS
Pushbuttons,contacts,
limit switches,etc.
ToOUTPUT
Solenoids, contactors,
alarmsetc.
A. Processor:
Processor is the central processing units (CPU) of the programmable controller, it executes the various logic and sequencing functions by operating on the PLC inputs to determine the appropriate output signals.
. Field sensors: switches, flow, level, pressure, temp. transmitters, etc. Field output devices: motors, valves, solenoids, lamps, etc.
B. Memory unit:
Memory unit is connected to the CPU, which contains the programs of logic, sequencing and I/O operation.
This memory unit is referred to as the user or application memory because its contains are entered by the user and also direct the execution of control program and coordinates I/O operations with the aid of system memory.
C. Power supply:
A power supply of 120v alternating current (ac) used to drive the PLC (some units operate on 240v ac)
These low voltages are used to operate equipment that many have much higher voltage and power ratings than the PLC itself.
D. Input/Output Modules:
1) Input Module:Input to the PLC are signals come from: Limit-switchs, Pushbutton, Sensors and other on/off devices.
2) Output Module:• Outputs from the controller are on/off signals to operate: Motors, Valves, and other devices required to actuate the process
E. Programming device:
Programming device is used to entered the required program into the memory of the processor.
THANK YOU…!!!