Weighing sensors are widely used in industrial weighing (such as belt scales, weighbridge scales, electronic scales, human scales, etc.), force detection, and tension pressure measurement. The general faults of the weighing sensor during on-site use are as follows.
1. The sensor is overloaded, and the user and manufacturer did not communicate clearly. The sensor range and actual force value, as well as the weight size, do not match, resulting in sensor overload and deformation of the sensor bridge arm resistance, causing circuit imbalance. The sensor cannot function properly, the output signal fluctuates, and there are phenomena such as infinite resistance.
2. The sensor lead is pulled apart, and the user did not take protective measures during use. The sensor lead is usually pulled apart at the sensor lead interface, which affects the sensor's unresponsiveness or sudden changes in measurement values. 3. Improper use of sensors, static sensors that have severe damage such as impact, shear, and torsion during use, making them unable to be repaired.
1. The sensor manufacturer provides sensor output sensitivity and power supply voltage at the factory, and we detect the sensor output signal based on these two parameters. The strain gauge type weighing force sensor outputs an analog signal millivolt voltage. For example, the sensor output sensitivity is 2.0mV/V, and the power supply voltage is DC10V. Two parameters can provide us with a linear relationship between the sensor excitation working voltage and the required DC10V. The sensor output signal corresponds to a 2.0mV output per 1V excitation voltage. For example, if the full scale of the sensor is 50KG, then the full scale output of the sensor is 20mV with a DC10V voltage. Based on this relationship, we use a multimeter mV gear to measure the sensor output signal. The no-load output of the sensor is normal at 0mV, which is greater than this value, but when it approaches this value, a change in value indicates that the sensor has zero drift. If the value is large, it indicates that the sensor is damaged or the internal bridge is a circuit, and the bridge arm resistance is asymmetric.
2. Determine whether the sensor strain gauge is damaged based on the sensor parameters provided by the factory, input resistance, and output resistance. The input and output resistance values of sensors vary from manufacturer to manufacturer. So this needs to be tested according to the manufacturer's labeling. Use a multimeter to measure the resistance between the power supply and ground, as well as the resistance between the signal wire and ground. If the resistance value is higher than the factory value, it indicates that the sensor has been overloaded and the strain gauge has deformed. If the resistance value is infinite, the strain gauge of the sensor is severely damaged and cannot be repaired.
3. Due to the frequent breakage of leads during the use of sensors, while the outer layer of the sheath wire is intact, we visually inspect the integrity of the sensor wire. We use the ohmic range of a multimeter to detect the continuity of the sensor wire. If the resistance is infinite, it is determined to break, and if the resistance changes, the contact is poor.
