PRESENTED BY:-
HEMANT RAJPUT

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PLC
P – PROGRAMMABLE
L – LOGICAL
C – CONTROLLER
concept of plc was developed in 1969-70.
First plc was made by modicon,france
PLC MANUFACTURER
ALLEN BRADLEY
SIEMENS
MITSUBISHI
MEESUNG (INDIAN)
DELTA
PLC CONTRIBUTIONS
Power supply
Communication
Input module
Output module
Processor
PLC Applications
Microprocessor, similar to that found in a PC, calculator, or your automobile
Extensively used to control manufacturing and treatment processes.
Can also accept directions:
Notification of alarm levels
Types of events to record
AUTOMATION
It is the system which use the controller and SCADA and it is the delegation of human control function to technical equipments
Increase production
Reduce man power
Improves quality
Reduces cost
SCADA
S –SUPERVISORY
C –CONTROL
A – AND
D – DATA
A – ACQUISITION
SCADA was developed in 1987 and they are black boxes and used to see and control from remote control room
Features of SCADA
Dynamic process graphics
Real time trends
Historical time trends
Alarms
Alarms history
Data based connectivity
Device connectivity
USE OF SCADA
SCADA enables a site operator to monitor and control processes from a remote location
Used to monitor and control any type of mechanical and electrical equipment at LF facilities

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Abstract
Over the years demand for high quality, greater efficiency and automated machines has increased in the industrial sector of power plants. Industrial automation supposes the operator responsibility on monitoring and controlling of processes in real time. They require continuous monitoring and inspection at frequent intervals. As the complexity of industrial processes increases, the need for remote controlling and monitoring form a central location also increases. A common term used to describe this solution is SCADA system, which make the operator function easier and also helps to reduce errors caused by human. While the SCADA is used to monitor the system, PLC is also used for internal storage of instruction for implementing functions such as logic, sequencing, timing, counting and various types of machine processes.
This report presents the latest trend of SCADA system architecture, which is usually three layer
SCADA system architecture depending on open system technology rather than a vendor controlled proprietary technology. Based on the architecture, in this report SCADA and PLC are described and general procedure to design and development of SCADA system is given. Finally application of SCADA system for ‘Control of Boiler’ and ‘Control of Induction Motor’ is described. Thus concluding that, due to recent technological advances, the automation has become technically and economically feasible for developing application in various sectors. Hence there is need to introduce SCADA system in advanced educational courses.
1. Introduction
A SCADA “Supervisory Control And Data Acquisition” is the generic terms for the hardware, software, and procedures used to control and monitor industrial process in real time. It can provide information in real time environment that identifies problem as they occur and take corrective actions when assistance is needed. Proper monitoring of process can maintain operations at an optimum level by identifying and correcting problems before they turn into significant system failures.
SCADA is associated with (i) the process industries, where it manages the activities of number of integrated operation units to achieve certain economic objectives for process and with (ii) the discrete manufacturing automation where it coordinates the activities of several integrating pieces of equipment in manufacturing systems, such as machines interconnected group by a material handling system. SCADA encompasses the collecting of information transferring to the central site, carrying out any necessary analysis and control, and then displaying that information on number of operator screens. The requirement control actions are conveyed back to the process.
The control actions are carried out by PLC (Programmable Logic Controller), which are used for system control. PLC is industrial computer in which control devices such as limit switches, push button, proximity sensors, etc provide incoming control signals into the unit. An incoming control signal is called an Input. Inputs interact with instruction specified in the user ladder program, which tells the PLC to how to interact with the incoming signals. The user program directs the PLC on how to control field devices like motor drivers, solenoid etc. A signal going out of the PLC to control a field device is called Output. This report describes recent trends of SCADA system architecture, such as three layer architecture [1]. Design and development of SCADA system based on three layer architecture for some application is included in this report.
2. Three layer SCADA system architecture
Figure 1, below illustrates the three layer SCADA system architecture [1]. This is the latest trend of SCADA system which depends on open system technology rather than a vendor controlled proprietary environment.
Fig. 1: Three layer SCADA system architecture.
As shown in the above figure1 SCADA system consists of three layers. They are
1. Supervisory control layer: Master station consist of one or more personal computers which are configured to be dedicated to master station duties, although they can function in a multi-purpose mode. The duties of master station may include trending, alarm handling, logging archiving, report generation, and facilitation of automation. These duties may be distributed across multiple PCs, either standalone or network.
Master stations have two main functions:
1) Periodically obtain data from PLCs (and other master or sub-master station).
2) Control remote devices through the operator station.
2. Process control layer: This layer consists of more than one device depending upon the situation, these devices like
1) Programmable Logic Controllers: PLC is a special purpose computer consists of CPU and different kinds of memory. Typically modern Remote Terminal Unit (RTU) use Ladder Logic programming approach. PLCs are quickly becoming standard in the control system.
2) Analog Input and Output modules: The configuration of sensors and actuators determines the quantity and the type of inputs and outputs on a PLC. Depending on the model and manufacturer modules can be designed. An analog input and output module 4,8,16 or 32 inputs or outputs.
3) Digital Input and Output modules: Digital input modules are typically used to indicate status and alarm signals.
3. Field instrument control layer: This layer mainly consists of sensors and actuators. Sensors perform measurement and actuators perform control. Sensors get the data and actuators perform actions depending on this data. The processing and determination of what action to take, is done by master control station i.e., SCADA.