The Use of Plc in a Boiler 07

8/6/2019 The Use of Plc in a Boiler 07

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Presented by:

EMAMALLY Bibi Yusrinah

HAULKHORY Bilal

HURADON Ritesh

RAMDOO ShalineeSELLAMUTHU Krishen

VEERAPEN Pegeeni


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Definition

A PLC (Programmable Logic Controller) is defined as a

digital electronic device that uses a programmable memory to store

instructions and to implement specific functions such as logic,

counting, sequence, timing, and arithmetic in order to controlmachines and processes.


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INSTRUCTIONS DESCRIPTION

LOAD Load logical state of start input

LOAD NOT Load logical state of start input andinvert

AND Logical AND operation

AND NOT Logical AND NOT operation

OR Logical OR operationOR NOT Logical OR NOT operation

OUT Output


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Step 1 Testing Input Status

PLC checks whether switches and sensors are activated or not

Step 2 Programming Execution

The PLC executes a program instruction by instruction and basedon the status of the inputs

Step 3 Checking Correction of Output Status

The PLC verifies the outputs signal and adjusts it as needed


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Scan time is defined as the cycle through the program which involvesthe reading of the inputs from the other modules, executing the logicbased on these inputs and then updates the outputs accordingly. The

scan time is a very rapid process which happens in the range of1/1000th of a second.


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The component that make a PLC works can be divided into threemain areas namely:

The RACK

The rack is the component that holds everything together andallows the card to communicate with the CPU

The CPU (Central Processing Unit)

The CPU accepts the downloaded logic from a PC. The CPU is thenplaced in run mode so that it executes the program and operates

the processThe Input/Output (I/O) section

The Input/Output system provides the physical connection betweenthe equipment and the PLC


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Step 1

At the beginning of each cycle, the CPU brings in all inputsignals from the module and stores it into an internal memorycalled the Process Input Image (PII)

Step 2

Once the PII is read, the CPU pointer moves in ladder programfrom left to right and from top to the bottom

Step 3

The CPU takes the status of input from the PII and processesall the rungs.

It is in turn stored in the internal memory but this time it iscalled the Process Output Image (PIQ)

Step 4

At the end of the scanning cycle, the CPU transfers the signalstates in the PIQ to the output module.


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Purity

Absence of air in the water


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Flow of fuel

Flow of steam


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Temperature of the steam generated

Temperature and Pressure inside the boiler


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SCADA is an application. SCADA stands for Supervisory Controland Data Acquisition and is a system that gets data about systemin order to control that system.

SCADA application has two elements:

The process/system/machinery

Network of intelligent devices that interfaces with the systemthrough sensors which enables a person to measure and controlspecific elements of the system


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SCADA system performs four functions:

Data Acquisition

Network Data Communication

Data Presentation

Control


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The Use of Plc in a Boiler 07