DESCRIPTION
The present set-up is designed to study a PID Controlled Flow Process in the industry. Water is pumped from the sump tank by means of a centrifugal pump to a Pneumatic Control Valve and after passing thorough the Rotameter it return back to the sump. The Differential Pressure transmitter with an Orifice meter is fitted in the water line. The flow of water in the line is sensed by the transmitter and communicated to the digital indicating controller. This measured variable is compared with the Set Point by controller and output is generated and given to I/P converter, which in turn supply the 3-15 Psig pressure to vary the opening of the Pneumatic control valve to eliminate the error observed. As the opening of pneumatic control valve varies, the flow of water in the line gets effected. This process goes on until the Set Point target is achieved. A ball valve is also provided in the water line to disturb the system and to observe the effect of disturbance. As the water returns in the sump tank again, the system operates in close circuit. Provided Rotameter enables to get the direct reading of flow of water in the line. These units along with necessary piping are supported in a well-designed housing and are fixed on base plate. The present set-up is completely computerized controlled. The Digital Indicating Controller have a facility to interface the system with computer which enables to change the PID parameters using computer. The educational software and data-logging package has been developed for unit. This software is compatible to interfacing unit designed by us. This software package provides a comprehensive educational software environment within which the PID investigations can be performed. This software is capable to tabulate the sample readings according to the requirement of experiment under study and results obtained can be compared. The real time data acquisition can be done by interfacing the set-up with computer using software. This software can be used outside the laboratory with the computer to familiarize the students with the equipment and procedures with the help of Flow Diagrams provided in the software. In flow diagrams Set Point, Process Variable and Controllers Output are visible on the screen and this data can be transferred in Excel Files for further calculations, plotting graphs etc. Software allows the user to have control on sampling time, data logging, printing the stored data, preparing spread sheets in Excel etc.
EXPERIMENTATION:
To study the open loop or manual control
To study the proportional control
To study the two mode (P+I) control
To study the two mode (P+D) control
To study the three mode (PID) control
To study the tuning of controller (Open loop method) using Zeigler-Nichols method.
To study the stability of the system using the BODE PLOT.
Auto Tuning
UTILITIES REQUIRED:
Water Supply.
Compressed Air Supply : 1 CMH at 3 BAR.
Electricity supply: 1 Phase, 220 VAC.
Computer: Pentium IV with CD Drive, Windows XP version and MS Office XP pre-loaded. One RS 232 Serial communication port free for interfacing unit.
Table for Setup support.
TECHNICAL DETAILS:
DP Transmitter Output 4-20 mA.
Orificemeter Material Stainless Steel.
Water Circulation FHP Pump Tullu/Champion make.
Water Tank Material Stainless Steel, Capacity 10 Ltrs.
Flow Measurement Rotameter.
Control Valve Compatible capacity with Pneumatic Actuator.
I/P converter Input 4-20mA, Output 3-15 PSIG
Pressure Regulator 0-2 kg/cm².
Pressure Gauge Bourdon type 0-2 kg/cm²
Piping Size 1/4”
Interfacing unit For input-output communication with auto/manual facility
Micro-processor Controller PID Setting, auto tuning, fully programmable with serial communication
Software For experimentation, PID control, Data logging, trend plot, offline analysis and printing.
Instruction Manual An ENGLISH instruction manual will be provided along with the Apparatus
The whole unit is assembled rigidly on a base plate.
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