BOILER AUTOMATION USING PROGRAMMABLE LOGIC CONTROLLER INTRODUCTION PLC applications are extensively used in industry to control and facilitate repetitive processes such as manufacturing cell management, fly-by-wire control, or nuclear plant shutdown systems. One of these applications is industrial automation which includes numerous automated processes. This again includes automation of boiler which demands determination of certain physical parameters (viz. pressure, temperature, etc.) & utilizing these parameters to make the boiler start-stop or function in any manner we want, but automatically, without involvement of any personal. PROJECT IN BRIEF OBJECTIVE: Designing of a PLC controlled boiler for production of steam. PROJECT AT A GLANCE: 1
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Boiler Automation Using Programmable Logic Control
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BOILER AUTOMATION USING PROGRAMMABLE LOGIC CONTROLLER
INTRODUCTION
PLC applications are extensively used in industry to control and facilitate repetitive processes
such as manufacturing cell management, fly-by-wire control, or nuclear plant shutdown systems.
One of these applications is industrial automation which includes numerous automated
processes. This again includes automation of boiler which demands determination of certain
physical parameters (viz. pressure, temperature, etc.) & utilizing these parameters to make the
boiler start-stop or function in any manner we want, but automatically, without involvement of
any personal.
PROJECT IN BRIEF
OBJECTIVE: Designing of a PLC controlled boiler for production of steam.
PROJECT AT A GLANCE:
1
L
OOVERALL PROJECT VIEW
SOFTWARE AND COMPONENTS USED:
KGL software (make LG)
PLC module (make LG)
Motor
Water reserve
Closed air tight container
Level sensor(Digital)
Temperature sensor with current output(Analog)
Pressure sensor(Analog)
Solenoid valve(Digital)
The most common parameters that have to be controlled in the boiler are temperature, pressure, water level. The controlling mechanism can be achieved by using microprocessor and microcontroller, PID controller or using PLC. Programmable logic control (PLC) provides an easy and sophisticated method to design automation in industry. It also provides easy trouble shooting method and flexibility to the industry.
Generally an industry has an emergency stop button to stop the whole process instantly if any error occurred during operation. The emergency stop buttons are normally closed type. To start the mechanism a start button (normally open type) switch is used which is connected after stop button. When start button is made ON the lower level sensor sense the water level below the lower level hence it start the motor to pump the water in to the boiler. The pump runs till the water reaches the higher level sensor. After that the pump stops running. The temperature sensor provides the temperature information to the PLC. If the temp. is less then the preset value the heater starts after 5 sec of motor OFF time. Temperature rises continuously and form water steam. The temp. should not rise beyond tolerance level of boiler hence the temp. should rise up to certain limit and the heater should stop at that moment. The temp. again decreases and if goes below preset value it start the heater. The above process continues. The steam produce in the boiler exert a pressure on the boiler which is picked up by the pressure sensor. If pressure reaches the preset value it make the valve open and steam with a definite pressure goes out through the pipe. The preset value of the pressure should be calculated carefully and it should not exceed maximum limit of boiler tolerance. This process result in decrease in water level and if falls below the lower level sensor the motor starts during which the heater stops and whole process repeats.
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FLOW CHART:
YES
YES
NO
NO
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START
Is stop button NC?
NO
Is start button NO?
Is LLS NC?
Is HLS NC?
Is heater timer NC?
START MOTOR
Is motor coil NO?
NO
NO
STOP MOTOR AND START MOTOR TIMER
Is upper temp. Reach
A
B C
NO
YES D
YES
NO
YES
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Is temp less then preset?
Is heater coil made NO?
Is LLS switch NO?
Heater memory coil is ON
A
Is motor timer NC?
NO
CB
E
YES
E
HEATER COIL IS OFF
Is heater mem. Coil NO?
NO
HEATER COIL IS on
NO
YES
YES
HEATER COIL IS OFF AND TIMER IS ON
A
Is press. Reaches
OPEN THE VALVEVALVE REMAIN CLOSED
NO
YES
STOP
NO
YES
YES
NO
DIFFERENT SECTIONS OF THE PROJECT: The project incorporates the requirement of a physical PLC trainer kit which is responsible for collection of data from field sensors (within the boiler), evaluate them & generate appropriate output for the boiler to operate in a specific desired procedure. Initially, we divided our project into four sections viz., power supply section, water supply section, boiler (including sensors) section, process controlling section.
Boiler Section: Boiling container, sensors (presssure,temperature & level sensors) & a heater assemble altogether to give rise to the boiler section.
Controlling Section: This section includes the PLC trainer kit which is responsible for data collection from field sensors, evaluation of collected data & generation of appropriate output signals for automatic actuation and termination of different peripherals incorporated in the overall system.
Water Supply Section: Water supply to the boiler is ensured by a water pump whose actuation & termination is controlled by the PLC trainer.
Power Supply Section: This takes care of the power requirements for the whole project. This mostly comprises of the circuits providing DC power for the field sensors and valves (solenoids).
APPLICATIONS: The main advantage of using PLCs is the drastic reduction in the requirement of electrical components in terms of number of switches, relays, wiring, etc.the applications of this project are solely the applications of a boiler i.e., production of steam and using it for numerous processes like rotating the generator fins and hence producing power for commercial or industrial purposes.
STAGES OF PROJECT DESIGN:
We divided the overall construction of the project in two stages. These are described as follows:
STAGE 1:
This stage basically focuses on:
(i) Software design & simulation
(ii) Hardware design
(A).Power supply &
(b) .Sensing unit
Level Sensing Unit
Temperature sensing unit
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SOFTWARE DESIGN & SIMULATION
The software design and simulation part of the whole project is done by using the software
“KGL”. This software is used to design the ladder diagram of the overall project simulation in
order to study it`s behaviour.The ladder design hence obtained is downloaded into the PLC CPU
and thereby generating appropriate output signals required for the simulation.
Features of KGL for Windows
KGL for Windows is the Programming and Debugging Tool for LG Master-K Series.
KGL for Windows has abundant Features as below.
1) Program Compatible between LG Master-K Series.
A user can use the Program (*.PGM) created in LG Master-K Series for the Program
created in other LG Master-K Series As well. The Program, Parameter or Variable/Comment
created in KGL-DOS or GSIKGL can be also used in KGL for Windows.
2) PLC System Configuration by Project Structure
KGL for Windows manages the User-Defined Program as one Project including
Parameter and Variable/Comment. Also a user can save a Program (*.PRG), Parameter (*.PMT),
Variable (*.VAR) or Comment (*.CNT) respectively and the stored each File can be used for
other Project files.
3) User Friendly Interface
Easy and useful interface for Creating, Editing and Monitoring.
4) Online Editing
A Real Time Editing is available in online mode. The Program edited in the online
condition can be downloaded automatically without stopping PLC Hardware.
5) Monitoring the Information from PLC
A user can easily monitor PLC status such as Error Status, Network Information and
System Status.
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6) Debugging and Self-diagnosis (in New MASTER-K Series)
Trigger and Forced I/O Enable are available for the accurate Debugging
Creating a Program
Creating a Ladder Program
This chapter describes creating a program in Ladder Window using the Tool Bar.
#After selecting the Normally Open Contact icon in the Ladder Tool Bar, Move the cursor to
the place to insert the
Contact
#Click the left button of the mouse or press Enter key, then the contact input dialog box appears.
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#Type in the contact name (M0000) you want to insert and click OK button or press Enter
key.
#Select the Output Coil icon in the Ladder Tool Bar and move the cursor to the next column
of P000.
Click the mouse button or press Enter key.
#Type in the Output Coil (P040) and click OK button or press Enter key.
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Create a Project
About a Project
#A Project is the highest level to communicate with PLC and KGL for Windows.
A Project consists of Program, Parameter and Variable/Comment of Device.
#KGL for Windows deals with User Defined Programs and includes all elements necessary for
describing a Project.
#A Project consists of 3 Items (Program, Parameter and Variable/Comment) and Monitoring
is activated when the Monitoring Window is opened. Each Item can be saved respectively for
another Project.
#Saved Items (Program, Parameter and Variable/Comment) can be used for creating other
Projects or to reuse for other Projects.
#A Project includes not only Program, Parameter and Variable/Comment, but also PLC type,
used status of KGL and various information registered for monitoring. Thus, when you reopen
the Project after saving a Project, the Window keeps the previous working condition.
#Only Program and Parameters can be downloaded to PLC.
#A Project is saved as *.PRJ File.
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Create a Project
#To create a New Project file, Select File--New Project… ( ) from the Project pull-down
Menu.
The New Project dialog box will appear as below.
#Open a Blank Project
#It creates a new Project.
#Create from Old Files
#To create a New Project using the already existed Item (Program or Parameters or
Variable/Comment),
Select Item or items to be used by clicking the Find button in the dialog box.
#Click OK button after registering Items.
#Up to 3 items can be selected and non-selected items are set to default (Initial data).
#After selecting PLC Type and Programming Language, press the OK button. Then Project,
Message and Program Windows will be opened.
#Create from DOS KGL file
#To create a New Project using Items (Program, Parameter and Variable/Comment) created in
KGL for DOS,
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Select PLC Type and Programming Language after selecting already created Items in KGL for
DOS. Then, a New
Project will be opened.
#Create from KGL file
#To create a New Project from KGL file, Select already created files (*.PGM, *.CMT) from
GSIKGL in the dialog box and select PLC Type and Programming Language.
Hot-Keys for Ladder Program Mode
Simulation part
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END OF SOFTWARE DESIGN & SIMULATION
****** ******
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HARDWARE DESIGN
CHIP SPECIFICATIONS:
1).LM35 (Precision Centigrade
Temperature Sensors)
Description:
The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is
linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage
over linear temperature sensors calibrated in °Kelvin, as the user is not required to subtract a
large constant voltage from its output to obtain convenient Centigrade scaling.