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