DATA LOGGING AND ANALYSIS BY VIRTUAL INSTRUMENTATION Nicolae Patrascoiu Adrian Marius Tomus Department of Automation, Industrial Informatics and Computers University of Petrosani Universităţii 20, Petroşani, România patrascoiu@upet.ro Abstract: Real-world data logging applications are typically more involved than just acquiring and recording signals, typically involving some combination of online analysis, offline analysis, display, report generation, and data sharing. In this paper we propose a virtual instrument (VI) that converts a PC into a data logger and also the same instruments are used to offline analysis of measured and recording data and to sharing data with another application like Excel. Measurement signals are converted into measurement data aid A/D converter CA3162E follow-up recording via parallel port. Keywords: data logging, A/D converter, parallel port, data acquisition, data analysis 1. INTRODUCTION Basic elements of a data logging and analyzing system are presented in figure1. Acquiring is the process of actually measuring the physical parameters and bringing them into your logging system. Online analysis consists of any processing done to the data while are acquiring. It includes alarms, data scaling, and sometimes control, among others. Logging is an obvious requirement of every data logging system. Offline analysis is everything done with the data after it has been acquired in order to extract useful information from it. The final functional block is made up display, reporting, and data sharing. These are all the “miscellaneous” requirements that fill out the functionality of a data logging system (National Instruments 2003a). 2. ANALOG-TO-DIGITAL CONVERSION In this paper we consider a stand-alone analog–to– digital converter CA3162E product by Intersil Corporation. The CA3162E and CA3162AE are I 2 L monolithic dual slope analog-to-digital converters that provide a 3 digit multiplexed BCD output. They are used with the BCD–to–Seven–Segment Decoders/Drivers and a minimum of external parts to implement a complete 3–digit display used in many digital multimeters (DMM) (Intersil 2002). Data Logging Online Analysis This analog–to–digital converter generate at output not a binary code and we consider the output signal done by a 7 bits word respectively 4 bits for BCD code of digit (BCD OUTPUTS) and 3 bits for digit selection (MSD, NSD and LSD). With these 7 bits code is necessary to display measured value and to store consecutive values into properly file so that these codes are acquired through parallel port (Ciascai, 1998). For this the ones 7 bits are connected Online Analysis Display, Sharing, Reporting Acquire Fig.1. Basic elements of a data logging and analysis system