The importance of TERMOCOUPLE to warehouse

Thermocopel Function

In the world of electronics, thermocouples are temperature sensors that are widely used to alter the temperature difference in the objects into voltage changes (voltage). Thermocouples are simple to install, and have the same type of standard connectors, and can measure the temperature within the temperature range large enough to limit the measurement error of less than 1 ° C.

How Thermocouples Work
In 1821, an Estonian physicist named Thomas Johann Seebeck discovered that a conductor (like metal) that given the differences in heat will produce a voltage gradient. This is called the thermoelectric effect. To measure the changes this summer, a combination of two kinds of conductors as well as frequently used at the end of the hot object to be measured. This additional conductor will then have many gradients of temperature, and voltage changes in opposite temperature differences of objects. Using different metals to complete the circuit will produce a different voltage, leaving little difference in voltage allows us to make measurements, which increases according to temperature. This difference generally ranged from 1 to 70 microvolt per degree Celsius for the range of the resulting combination of modern metal. Some combinations became popular as industry standards, judging from the cost, availability, convenience, melting point, chemical capability, stability, and results. It is important to remember that the thermocouples measure the temperature difference between the 2 points, not absolute temperature.

In many applications, one connection (cold connection) is maintained as a reference temperature, while others linked to the object of measurement. Thermocouples can be connected in series with one another to make termopile, where each connection that heat is directed to higher temperatures and all the cold junction to a lower temperature.

That way, the voltage on each thermocouple to be increased, which allows for use on higher voltage. With the constant temperature at the cold junction, which is useful for measurements in the laboratory, it is simply not easy thermocouples used for many indications of direct connection and control instruments. They add cold artificial connection to their circuitry that is other equipment that is sensitive to temperature (such as thermistor or diode) to measure the temperature of the input connections on the equipment, with the specific aim of reducing the temperature gradients between the edges.

Here, the stress that comes from a known cold relationship can be simulated, and good correction can be applied. This is known as cold relationship compensation. Usually, the thermocouple is connected by means of an indication by a wire cable called an extension or compensation. The goal is clear. Extension cable to use the wires with the same amount used in thermocouple kondoktur itself. These cables are cheaper than the thermocouple wires, although not too cheap, and usually produced in an appropriate form for the transport of long-distance - generally as a closed flexible wire or multi-core cables. These cables are typically has a specification for a larger temperature range than the thermocouple wires. This cable is recommended for high accuracy. Cable compensation on the other hand, less precise, but cheaper.

They wear small differences, usually a mixture of low-cost conductor materials that have the same coefficient of thermoelectric thermocouple (working in a limited temperature range), with results that are not as accurate as extension cords. This combination produces output similar to the thermocouple, but the operating temperature range of the cable compensation is limited to keep the small error obtained. Extension or compensating cable must be selected according to the needs of the thermocouple. The election will produce a voltage proportional to the temperature difference between hot and cold connections, and the pole must be connected correctly so that the additional voltage added to the thermocouple voltage, replace the temperature difference between hot and cold connections.