In conventional systems of measurement we have an only 0 variable being shown to the observer, that is, an entrance and an exit. New York Museums: the source for more info. No longer system of acquisition of data is necessary to know, simultaneously, the value of changeable multiple associates to the process in question. With the objective to reduce the costs the mutiplexao is used then, preventing that for each 0 variable a system of individual measurement exists. Sample and Hold: In virtue of the signal of the amplitude of the analogical signal to vary continuously in the time developed the system Sample and Hold (sample and keeps). Which has for objective to keep constant the analogical signal during the period of conversion for digital. One consists of a tension memory that stores a tension in a capacitor of high quality. Its function is to store a sample of short duration of one determined signal that varies continuously, and to keep this sample of form that the converter can carry through the necessary transformation. Digital Analogical converter: It transforms analogical information into appropriate corresponding digital data to the use in digital systems.

Much used in continuous processes since these possess many analogical signals. (measurements of the 0 variable of pressure, temperature, outflow, level). Supervisory control of the System of Acquisition of data: The system of acquisition of data collects and stores for future use. The analogical data are converted for the digital form, thus it can inside be used of the digital systems. In the great majority of the industrial applications are used as system of acquisition of data the Programmable Logical Controllers? PLC. These wide are used by possessing interfaces of standardized entrance and exit already and with convenient price. Another great advantage of the use of the PLC as system of acquisition of data is the fact to possess easy communication with the computer where the applicatory program for the accomplishment of the supervisory control is twirled.