Rajan Sarkar

Design and Implementation of Real-Time Flow Measurement System Using Hall Probe Sensor and PC-Based SCADA

A rotameter is a variable-area-type flow rate measuring instrument in which the position of a metallic float in a transparent conical tube is taken as a flow rate indicator. It has the disadvantage that it is a local indicating type instrument and special type of transducer is used for its remote indication. In this paper, a noncontact flow rate measurement technique using Hall probe sensor and rotameter is designed, developed, and tested. In this design, a float carrying a thin circular permanent magnet is used, and a Hall probe sensor placed outside the rotameter tube has been used to sense the variation of magnetic field of the magnet with the variation of float position. A signal conditioner unit has been used to convert the Hall probe sensor output into 1-5 V dc signal. This dc signal output of the signal conditioner has been sent to a PC-based flow indicator through optoisolator and analog input channel of a data acquisition system (DAS) card. The PC-based flow indicator has been designed using the Lab Tech Note Book Pro software and the PC-based supervisory control and DAS. A theoretical equation has been derived to explain the operation of the system. The performance of the system has been tested experimentally, and the experimental results are reported in this paper. A very good repeatability and linearity of results has been observed.

Design of a Flow Transmitter Using an Improved Inductance Bridge Network and Rotameter as Sensor

A rotameter is a variable area type flow sensor. It is generally used as a local indicator and display unit. Hence, a special technique is needed to transmit and to display the reading of a rotameter at a remote distance. In this paper, an improved inductance bridge-type technique has been developed to convert the float movement of the rotameter into an electrical current signal, which can be transmitted to a remote indicator. A straight ferromagnetic wire attached to the float of the rotameter acts as a sensing element of the proposed rotameter transducer. The movement of the wire as a result of fluid flow variations inside an inductive pickup coil changes the self-inductance of the coil with the changes in flow rate. An improved inductance bridge network has been used to measure the self-inductance of the coil. It has been observed that the variation of the self-inductance of the pickup coil as well as the variation of the transducer and transmitter outputs with flow rate has a very good linearity and repeatability. The necessary theoretical equations, along with the experimental results, are reported in this paper.

Study of a thyristor driven pump as a flow indicator

In the present paper, the load current of a thyristor driven pump has been utilized as a mass flow sensing parameter of a fluid being lifted by the pump. The motor load current has been sensed by an opto-isolator based circuit and the output of this circuit has been displayed in a PC monitor using Labtech Notebook Pro software. A theoretical equation relating the output of opto-isolator circuit with mass flow rate has been derived and experimental study has been carried out to verify this theoretical equation, assuming the volume flow rate of water at constant room temperature to be proportional to mass flow rate. The experimental results are presented in the paper. It has been observed that the opto-isolator output and the on-line display in PC monitor both vary almost linearly with mass flow rate. Percentage deviation of the experimental results from ideal linearity and repeatability in terms of standard deviation are found to be within tolerable limit.

A Review Work on Reconstruction of ECG Wave from Fourier Harmonic Components

Analysis and reconstruction of ECG wave from sampled data is an important aspect in estimating the physiological condition of heart as well as in transmitting the ECG data to a remote location. In the present paper software based off line Fourier analysis technique has been reported to find the harmonic components of ECG wave of a normal subject. The respective Fourier harmonic data have been combined to reconstruct the ECG wave and thus to find the maximum number of harmonic present in a normal ECG wave. The analysis results are reported in the paper and it has been observed that complete reconstruction of ECG wave is possible if only fifteen Fourier harmonic data are considered. Thus transmission of ECG wave may be easier since fifteen harmonics amplitude are only required to be transmitted along with their respective phase angles.

Design of a PC based real time mass flow indicator using AD590 as sensor

Mass flow rate of liquid is an important parameter to be measured and controlled in a process industry. In this paper, the design of a PC based mass flow indicator has been studied using a well known temperature sensing IC AD590. The temperature sensing IC AD590 has been used as a flow sensing element and the effect of fluid temperature has been eliminated by using four identical IC units. Four IC units are connected in the differential mode. The output of the differential circuit is sent to opto-isolator circuit through a signal conditioner circuit. LabTech Notebook Pro software has been used for the flow rate display on a PC monitor. The output of this circuit has been theoretically related with flow rate of the fluid. Experiments have been performed to find the operational characteristics of the transducer. In this paper, the experimental results are presented, a good performance characteristic has been observed.

Study of PID and FLC based water level control using ultrasonic level detector

In the industrial sector there exist parameters like level, temperature, flow, vibration which needs precise control. Conventional control system adopts PID technique to control its parameter but cannot achieve desired accuracy because of several disadvantages. So to overcome these drawbacks, fuzzy logic control system is adopted which gives better performance. Therefore, an attempt has been made to study the comparison between conventional PID controller and Fuzzy logic controller using ultrasonic level sensor. In this paper, we have designed a real setup of microprocessor based PID controller as well as designed simulation system of PID and fuzzy logic controller for water level control by using Fuzzy Logic Toolbox and Simulink in MATLAB software.

Design and development of an optical pressure sensing system using bellows as primary sensor

A new optical type pressure sensing system is proposed in this paper. Bellows, an elastic type sensing element is used to indicate the pressure in the form of displacement of bellows element. For automated process industries, the signal is required to be send to a remote location like control room. In order to send the mechanical movement of bellow corresponding to the applied pressure, to a control room the signal is to be converted in the form of electrical, pneumatic or optical signal. For inflammable industries optical signal transmission is preferred. In this work the displacement of bellow element is first converted into an electrical signal using hall probe sensor then it is converted into an optical signal using (MZI) Mach-Zehnder Interferometer. The proposed sensing system is designed and its theory of operation is developed. The experiment was done on the proposed system and the experimental characteristic shows very good linearity with excellent repeatability.