DESCRIPTION:

The setup consists of a process tank in which compressed air enters through a Pneumatic control valve. The pressure transmitter is fitted on the process tank. The air pressure in process tank 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 pressure in the Process Tank gets effected. This process goes on until the Set Point target is achieved. A ball valve is also provided in the process tank to disturb the system and to observe the effect of disturbance. 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. The software environment base is of Lab view of NATIONAL INSTRUMENTS, USA. This software is compatible to interfacing unit designed by “Lab Smith”. 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.

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:

•  Compressed Air Supply : 1 CMH at 6 BAR.
•  Electricity supply: 1 Phase, 220 VAC.
•  Computer: Pentium IV, Windows XP version pre-loaded. One RS 232 Serial communication port free for interfacing unit.
• Table for Setup support.

TECHNICAL DETAILS:

Ordering Details: