With the rapid development of electronic metering technology, the belt scale measuring system is developing in a fast, continuous and precise direction. The core of the high-precision metering system is the load cell. Its performance depends mainly on two aspects, one is the base material of the strain gauge, and the other is the strain core material of the strain gauge sensitive grid. Regardless of which strain gage is used, the drift of the strain gauge caused by temperature changes cannot be ignored.
The strain gauge attached to the sensor elastomer, under the influence of the load, except for the change of the resistance value with temperature, the other physical properties of the elastomer material and the strained alloy also change somewhat. These changes are pure strain gauges. It is a false change due to temperature changes. For the sensor, the temperature drift caused, which in turn affects the metering accuracy of the entire weighing system.
Solution :
The temperature self-compensation of the load cell is mainly due to the temperature self-compensation of the resistance strain gauge. On this basis, the zero temperature drift of the sensor can also be compensated by line compensation. In actual work, the sensor is often not at a constant temperature. Work, so the zero point will drift with temperature as the sensor is not subjected to external forces. This change will affect the accuracy and performance of the sensor, sometimes to an unusable level. The compensation method is to connect a temperature-sensitive resistor in series on a bridge of the resistor, and achieve the purpose of compensation by successive approximation.
For the compensation of the output sensitivity, a compensation resistor can be symmetrically connected in series at the input end of the bridge. When the temperature rises, the resistance value of the compensation resistor becomes larger, thereby reducing the bridge voltage, and the purpose is to compensate the output sensitivity.