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Measurement error of platinum thermal resistance in infrared thermometer
- 2019-03-18-

When the infrared thermometer is used, the measurement of platinum thermal resistance is affected by many factors. Today Wuxi very Xiang Technology Co., Ltd. takes you to understand:

With the two-wire system, the sensor and its supporting products can be calibrated in the laboratory to eliminate measurement errors caused by the internal lead resistance.

The three-wire system is a wiring form commonly used in industrial production. Its working principle is: the measurement circuit is generally a balanced bridge. Platinum resistance is used as a bridge arm resistance of the bridge. One wire is connected to the power terminal of the bridge. The remaining two are connected to the platinum resistance bridge arm and its adjacent bridge arm respectively. When the bridge circuit is balanced, the resistance change of the wire has no effect on the measurement result, so the measurement error caused by the wire resistance is eliminated. .

The working principle of the four-wire system: four-wire measurement, using two test leads to provide a constant current, and the other two test leads measure the voltage drop of the unknown resistance. Under the condition that the voltmeter input impedance is high enough, the current hardly passes through the voltmeter In this way, the voltage drop on the unknown resistance can be accurately measured, and the resistance value can be obtained by calculation. Because the four-wire connection can reduce the resistance value of the wire and make the measurement more accurate.

Since the temperature sensing element is led out by the lead wire, the material of the lead wire is different, and the line resistance is also different. When the inner lead of the sensor in the infrared thermometer is long, there is a large lead resistance. The resistance value of the thermal resistance is the resistance of the sensor plus the resistance of the inner lead. Therefore, during the measurement, if the resistance value of the lead wire is large, the measured resistance value will exceed the allowable error range, so that the detection result of the sensor is unqualified.

Wuxi Jixiang Technology Co., Ltd. is located on the shores of the beautiful Taihu Lake and Lihu Lake. It is a technology company specializing in infrared temperature measurement, infrared thermal imaging, and intelligent instrument technology. For more than ten years, the company has upheld the professional spirit and Users provide sincere and high-quality services, various advanced and reliable automated intelligent products, widely used in

Integrated infrared thermometer