The primary aim of this paper is to get advantage of computer based system [10]. The Hardware PID is replaced with soft PID that has equal controlling capabilities as that of instrument. Virtual Instrumentation PI controller is implemented using software called LabView developed by National Instruments. We have used a Data Acquisition board (DAQ) for interfacing with the hardware. This DAQ card is product of the same company National Instruments [7] [2]. The process is a Multi-loop Trainer set up mounted with a tank whose level has to be controlled using a feedback control loop. The flow of project execution is: The measured inputs to the designed PI will be provided by Level transmitter. The designed PI will be generating the necessary controlling electronic signal. This signal will be acquired by DAQ card. The DAQ card transfers it to the I / P converter which will convert the electrical pulses 4-20mA into pneumatic signal 3-15psig to actuate the control valve. This virtual PID can replace hard wired PID. By virtual PID implementation we are getting freedom of reconfiguration and flexibility of control strategy.

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LabView PID DAQ Hardware / Software process variable control signal etc.