Suryaprakash S

  Micro Computer Based Data Acquisition System: Computer Based Data Acquisition System – If a large number of inputs are to be measured, some equipment is needed to measure them and display the results in a meaningful and operationally useful fashion. All this is possible with Data Acquisition System, which utilises a  computer  driven visual display unit (CRT) as an operator aid. A screen display can be obtained within two seconds by pressing a button. Information may be displayed only when called up. The screen display can be designed in several ways, using a combination of graphical and numeric displays, so as to be of maximum utility to the operator. Data Acquisition System aids operate in the following manner. Display information instantly in condensed, understandable and legible manner so that it can be easily assimilated. Display spatial as well as time variation. Display vital  parameters  grouped together logically and concisely, eliminating the need of looking at many scatter

  Compact Data Logger: Compact Data Logger – A typical unit provides 60 channels of data in a 20 x 40 x 60 cm box weighing about 20 kg. Most manufacturers offer local or remote add-on scanners to expand to about 1000 channels. Scan rates are modest usually (1 — 20 channels per second) and though versatile signal conditioning is provided, the signal processing capability is limited to simple functions such as (mx + b) scaling, time averaging of single channels, group averaging of several channels, and  alarm  signaling when preset limits are exceeded. However, most units do allow interfacing to computers, where versatile processing is possible. Compact Data Logger of this class utilise a built in microprocessor to control the interval of operations and carry out calculations through a single amplifier — A/D converter, which is automatically ranged or gain switched under program control to accommodate the  signal level  of each channel, as shown in Fig. 17.26. This is not useful for appl

  Single Channel Data Acquisition System: A Single Channel Data Acquisition System consists of a signal conditioner followed by an analog to digital (A/D) converter, performing repetitive conversions at a free running, internally determined rate. The outputs are in digital code words including over range indication,  polarity  information and a status output to indicate when the output digits are valid. A Single Channel Data Acquisition System is shown in Fig. 17.3. The digital outputs are further fed to a storage or printout device, or to a digital computer device, or to a  digital computer  for analysis. The popular Digital panel Meter (DPM) is a well known example of this. However, there are two major drawbacks in using it as a DAS. It is slow and the BCD has to be changed into  binary coding , if the output is to be processed by digital equipment. While it is free running, the data from the A/D converter is transferred to the interface register at a rate determined by the DPM itsel

Data Acquisition System: A typical Data Acquisition System consists of individual sensors with the necessary signal conditioning, data conversion, data processing, multiplexing, data handling and associated transmission, storage and display systems. In order to optimise the characteristics of the system in terms of performance, handling capacity and cost, the relevant sub systems can be combined together. Analog Data Acquisition System is generally acquired and converted into digital form for the purpose of processing,  transmission , display and storage. Processing may consist of a large variety of operations, ranging from simple comparison to complicated mathematical manipulations. It can be for such purposes as collecting information (averages, statistics), converting the data into a useful form (e.g., calculations of efficiency of motor speed, torque and power input developed), using data for controlling a process, performing repeated calculations to separate signals buried in the

  Analog to Digital Converter & Its Working Almost every environmental measurable parameter is in analog form like temperature, sound, pressure, light, etc. Consider a temperature  monitoring system  wherein acquiring, analyzing, and processing temperature data from sensors is not possible with digital computers and processors. Therefore, this system needs an intermediate device to convert the analog temperature data into digital data in order to communicate with digital processors like microcontrollers and microprocessors. Analog to Digital Converter (ADC) is an electronic integrated circuit used to convert the analog signals such as voltages to digital or binary form consisting of 1s and 0s. Most of the ADCs take a voltage input as 0 to 10V, -5V to +5V, etc., and correspondingly produces digital output as some sort of a binary number. What is Analog to Digital Converter? A converter that is used to change the analog signal to digital is known as an analog to digital converter or