Mechatronics

Mechatronics

Introduction: Temperature Sensors

The temperature is of fundamental importance in many industrial processes. Therefore it is essential to have an accurate measurement. Inaccurate temperatures can have serious consequences, such as reducing the life of your computer if you have an overheating of a few degrees. Teh temperature represents its thermal state in relation to the ability to transmit heat to other bodies. It is an index of the average value of the kinetic energy internal, linked to agitation of its molecules. Sensors and actuators are examples of transducers. A transducer is a device that through which the energy becomes heat, light, sound, pressure, motion, flow, etc. into another electrical device and is generally used to measure and eventually control the energy relatively easily. The temperature sensors exploit different physical phenomena that occur when they are subjected to a temperature difference. The best known are the Seebeck effect, the Thomson effect and the effect Peltier. They are the combining of two different conductor elements and by varying the temperature of the junction, between the ends of the two conductors is born an emf AB proportional to the temperature difference T and linked to nature of the two metals.

The temperature is an intensive quantity, which can be measured in two ways different ways:

atomic scale, it is related to the average kinetic energy of the constituents of matter;

At the macroscopic level, some properties of the body depend on the temperature (specific volume, electrical resistance, etc) that can be selected for build temperature scales.

The oldest is the centesimal scale (1742), assigning arbitrary values ??to 0 and 100 degrees melting ice and boiling water under normal atmospheric pressure. It is defined as the temperature-dependent phenomenon chosen (expansion fluid) to form the standard thermometer, preferably using the Celsius scale, defined from the Kelvin scale:

(1)

This scale, which is the international system, is not dependent on any particular phenomenon and therefore defines absolute temperatures. Absolute zero (-273.15 ° C) has been approached a few millionths of a degree. The physical phenomena occur at very low temperatures experiencing significant applications (superconductivity). In the field of high temperature plasma torches can high power lasers used for research into controlled nuclear fusion give, for a very short time, temperatures above 100 millions degrees.

Discussion

Theory and Principle

Teh temperature sensors works like a diode breakdown voltage which is directly proportional to the temperature reaches the surface. The analog-digital in this practice is going to be useful to get the signal from the sensor provides, turn it into a digital value. The digital value will be obtained through a programmable memory that will indicate by means displays the temperature value corresponding to the digital value. The operation of the ADC is based on the subtraction of its terminals Vin + and Vin-. The tension we get, translates to a digital value. Thus, for Vin equal to or greater than Vin +, we obtain at the output the value 0000000, can thus fix the point where we want to start the ...