l Control:
By control we mean that
the physical variables/process variable are kept constant as the desired value.
l Type of control:
1.
Manual control
2. Automatic control
l Type of Automatic control:
1. Open loop control
2. Close loop control
l Type of Close loop control:
1.
Feed-forward control
2. Feed-back control
l Advantage of Automatic control:
1.
Increased production
2. Improve quality
3. Saving in Raw material, Energy, Manpower.
4.Increased Safety, etc.
l PLC:
A Programmable Logic Controller is a special
form of microprocessor based controller that uses a programmable memory to
store instruction and to implement function such as logic, sequence, timing,
counting, comparing and the processing of analog signals in order to control
machines and process.
l Advanced PLC:
The modern advanced PLC’s can handle various
types of analog signals. It can handle Thermocouple (TC), Resistance
Temperature Detector (RTD), Pulse, High speed count signal, Voltage, Current,
etc.
So the modern PLC can provide a complete
solution for operating and process plant.
l General specification of
PLC:
1.
Input output specification
2.
Control specification
3.
Peripheral function
4.
Maintenance function
l SCADA system:
It means Supervisory Control and Data
Acquisition. SCADA is graphical software for Human Machine Interface (HMI).
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