What caused the error of the thermal resistance thermometer1

All the instruments in use of the time there is a certain fault, thermal resistance is no exception. Thermal resistance thermometer at the time of measurement error is also will appear the error, so what is the cause of thermal resistance thermometer error? As long as find a reason to quickly solve, the following project is to introduce what is the cause.

( 1) Heat transfer error.

it is due to the lateral temperature when not in contact with the object to be tested fully not reach thermal equilibrium caused by the error, such as when using should, in accordance with the relevant specification more careful.

( 2) Degree of error.

standardized thermal resistance index table is produced by statistical analysis, adopted by the thermal resistance of concrete, however, because the material, manufacturing process and differ somewhat, this creates a degree error, such as who do not tally with the nominal resistance value and the introduction of error.

( 3) Since the thermal error.

this is due to the measurement of current flows through the heat resistance in the process of falling in to produce the additional error caused. It is related to the current size and heat transfer medium. Industry in our country with the thermal resistance of limiting current is less than 6 ma, so that you can limit the temperature error within 01 ℃.

( 4) The error of the measuring circuit and display instrument.

it is by the level of accuracy and display instrument itself line resistance. If use Cu50 type copper resistance temperature measurement, the resistance of the copper wires under prescribed conditions for 50, if measured and remote instrument for 4070 sichuan ℃, environment temperature changes at this time the two wire connection wires can bring about 2 ℃ to measure error, three-wire system connection will bring the error of 01 ℃. In addition, the lead resistance, change the limits of the connection wire in also will cause error.

( 5) Other error.

this means other than the above error by blocking defective insulation, inserted depth is not enough, such as thermal resistance degradation caused by the error.

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