Sensor manufacturers discuss the temperature compensation method of strain gauge weighing sensor
Release time：2017-03-04
Author：admin
Clicks：1994
Strain-type weighing sensor is composed of resistance strain gauge bridge balance principle to convert physical quantities into electrical quantities of the device, everyone knows that metal resistance changes with stability, which will affect the performance of strain-type weighing sensor, then we should change the weighing sensor temperature drift how to compensate?
(1) The resistance of the strain gauge of the weighing sensor based on the theory of temperature error varies only with the strain, but in fact, the resistivity and shape of the resistance wire will change with the temperature, so the resistance value will also change, resulting in temperature error. When the temperature changes, the relative resistance of total resistance is
Among them, alpha t is the resistance temperature coefficient of the sensitive gate material, K is the strain gauge sensitivity coefficient, alpha G is the expansion coefficient of the specimen, and alpha s is the expansion coefficient of the strain gauge sensitive gate material. The corresponding false contingency is
In order to eliminate this temperature error, temperature compensation measures must be adopted.
(two) temperature compensation usually compensates for temperature errors. There are self compensation method and line compensation method.
1. self compensation method
(1) The principle of single wire self-compensation method is to select the temperature coefficient and expansion coefficient of the grating wire properly so as to make the grating wire self-compensated.
So that the e t=0. This self-compensating strain gauge is easy to process and low cost, but it is only suitable for specific specimen materials, and the temperature compensation range is narrow.
(2) The combined self-compensation method consists of two kinds of metal wires with two different temperature coefficients in series. One is to select two kinds of metal wires with different resistance temperature coefficients; the other is to use two kinds of metal wires with the same resistance temperature coefficients, but the resistance formed by the two kinds of metal wires is electrified separately. In the two arms of the bridge.
2. the common compensation method for line compensation is bridge compensation. It uses the strain gauge as one arm of the bridge, and the compensator with the same material as the strain gauge as the other arm of the bridge, so that the compensator and the strain gauge have the same temperature change law. According to the resistance of the adjacent arms of the bridge changes at the same time, the output of the bridge will not be affected. The temperature error of differential bridge can be compensated directly because two strain gauges of the same type are used, but the strain direction is opposite. The bridge compensation method is simple and feasible, and the common strain gauge can be used to compensate various materials in a wide temperature range, so it is commonly used. Of course, in addition to the use of compensator or differential strain gauge, also can use thermistor to compensate pressure sensor.
(1) The resistance of the strain gauge of the weighing sensor based on the theory of temperature error varies only with the strain, but in fact, the resistivity and shape of the resistance wire will change with the temperature, so the resistance value will also change, resulting in temperature error. When the temperature changes, the relative resistance of total resistance is
Among them, alpha t is the resistance temperature coefficient of the sensitive gate material, K is the strain gauge sensitivity coefficient, alpha G is the expansion coefficient of the specimen, and alpha s is the expansion coefficient of the strain gauge sensitive gate material. The corresponding false contingency is
In order to eliminate this temperature error, temperature compensation measures must be adopted.
(two) temperature compensation usually compensates for temperature errors. There are self compensation method and line compensation method.
1. self compensation method
(1) The principle of single wire self-compensation method is to select the temperature coefficient and expansion coefficient of the grating wire properly so as to make the grating wire self-compensated.
So that the e t=0. This self-compensating strain gauge is easy to process and low cost, but it is only suitable for specific specimen materials, and the temperature compensation range is narrow.
(2) The combined self-compensation method consists of two kinds of metal wires with two different temperature coefficients in series. One is to select two kinds of metal wires with different resistance temperature coefficients; the other is to use two kinds of metal wires with the same resistance temperature coefficients, but the resistance formed by the two kinds of metal wires is electrified separately. In the two arms of the bridge.
2. the common compensation method for line compensation is bridge compensation. It uses the strain gauge as one arm of the bridge, and the compensator with the same material as the strain gauge as the other arm of the bridge, so that the compensator and the strain gauge have the same temperature change law. According to the resistance of the adjacent arms of the bridge changes at the same time, the output of the bridge will not be affected. The temperature error of differential bridge can be compensated directly because two strain gauges of the same type are used, but the strain direction is opposite. The bridge compensation method is simple and feasible, and the common strain gauge can be used to compensate various materials in a wide temperature range, so it is commonly used. Of course, in addition to the use of compensator or differential strain gauge, also can use thermistor to compensate pressure sensor.