PC Controlled Function Generator Using Direct Digital Synthesis (DDS) Technology For Electrical Capacitance Tomography

2012 ◽  
Author(s):  
Ruzairi Abdul Rahim ◽  
Chin Heng Teo ◽  
S. Sulaiman ◽  
M. S. Abdul Manaf
Keyword(s):  
Flow System ◽  
Sine Wave ◽  
High Accuracy ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Direct Digital Synthesis ◽  
Function Generator ◽  
Tomography System ◽  
Digital Synthesis ◽  
Capacitance Tomography

Penjana frekuensi telah digunakan secara meluas dalam pelbagai jenis ujikaji. Ia digunakan untuk menjana pelbagai bentuk gelombang (gelombang sin, gelombang segiempat dll) pada frekuensi dan lebar jalur tertentu. Satu daripada aplikasinya ialah dalam Proses Tomografi jenis Kapasitif (ECT) di mana ia digunakan untuk menyalurkan maklumat mengenai keadaan aliran. Kertas kerja ini menjelaskan bagaimana mereka bentuk sebuah Penjana Fungsi yang Dikawal oleh Komputer Peribadi yang ekonomi untuk kegunaan ujikaji makmal. Rekaan ini berbeza dengan penjana fungsi manual kerana ia hendaklah dikawal secara digital. Dalam kes ini, teknologi DDS (Direct Digital Synthesis) digunakan kerana cip DDS adalah digital secara semulajadinya. Analisis telah dibuat untuk memeriksa ketepatan keluaran fungsi dari segi frekuensi dan amplitudnya. Kata kunci: Penjana frekuensi, sintesis secara terus (DDS) A function generator is widely used for experimental work and testing to generate various types of waveform (sine, square, triangle, etc) with a particular frequency bandwidth. One of its applications is in generating waveform for the ECT (Electrical Capacitance Tomography) system. ECT is used to retrieve the details of material in a flow system. An economical PC Controlled Function Generator was designed for the use of waveform generating in ECT. For the ECT system, high accuracy and frequency waveforms are needed. Three basic waveforms are required; the sine wave, square wave, and triangular wave. The objective is to build a function generator which is capable of generating high accuracy waveforms with acceptable distortion and stability. An interfacing system between a PC and the function generator was also selected and developed with the purpose of producing accurate amplitude and frequency of the waveforms. This interfacing allows remote control to the function generator for a wider usage. Key words: Function generator, direct digital synthesis (DDS)

Electric Potential Distribution of Electrical Capacitance Tomography System at the Centre of Pipe Based on Segmented Excitation

2013 ◽  
Vol 64 (5) ◽  
Author(s):  
Shahrulnizahani Mohammad Din ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling
Keyword(s):  
Electric Potential ◽  
Pipe Flow ◽  
Potential Distribution ◽  
Electrical Potential ◽  
Comsol Multiphysics ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Tomography System ◽  
Resolution Problem ◽  
Capacitance Tomography

Electrical capacitance tomography (ECT) is one of the systems used to inspect closed pipe flow. This paper will present the proposed segmented excitation of electrodes with a focus on the low resolution problem.  Modelling of 8, 12 and 16 electrodes is done using COMSOL Multiphysics. The number of excitation electrodes is increased until half of the electrodes are excited at the same time. The electrical potential distribution is analyzed and the voltage value at the centre of the pipe is captured. The results show that there is improvement of electrical potential and voltage value in proportion to the number of electrodes excited at the same.

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