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It Is Imperative To Carry Out Temperature Compensation For Pocket Electronic Scales

Update:02-09-2022
Summary:

    For a high-precision strain sensor, it is not enoug […]

    For a high-precision strain sensor, it is not enough for a digital pocket scale to form a bridge measurement circuit with four strain gauges. , temperature changes, and other factors, the sensor is bound to produce certain errors.

    In order to improve the precision and temperature stability of the pocket electronic scale, temperature compensation is necessary. The temperature compensation method of zero-load output is to insert a temperature-sensitive resistor in series in a bridge arm of the bridge circuit and connect the zero-load temperature compensation resistor rt to the bridge arm with a small temperature coefficient according to the drift size and polarity. The temperature compensation resistor rt is generally made of pure copper or pure nickel wire with a large temperature coefficient of resistance. After compensation, the zero drift error of the sensor can be reduced to 0.03%/10°C of the full scale within a few tens of °C. Output Sensitivity Temperature Compensation Because the elastic modulus E of the elastic element changes with temperature and the sensitivity coefficient k of the strain gauge changes, the output sensitivity of the sensor also changes with temperature. The rule is that its value increases as the temperature increases. In order to compensate for this error, materials with a large temperature coefficient of resistance and high resistivity are generally used to make compensation resistors connected to the bridge output. When the temperature rises, the resistance value of Rm increases and its voltage drop also increases, which reduces the actual supply bridge voltage and reduces the sensor output, thereby offsetting the error caused by the temperature rise and achieving the purpose of compensation.

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