A simple method to judge the quality of load cell
Load cell weighing sensor concept:
Load cell weigh sensor is actually a device that converts the mass signal into measurable electrical signal for output. The actual working environment of the sensor should be considered before using the sensor weighing load cell, which is very important for the correct selection of the weighing sensor. It is related to the normal operation of the weighing load cell sensor, its safety and service life, and even the reliability and safety of the whole weighing instrument. In terms of the basic concepts and evaluation methods of the main technical indexes of load cells weighing sensor, there are qualitative differences between the new and old national standards. There are S-type load cell sensor, cantilever type load cell sensor, spoke type load cell sensor, plate ring type load cell sensor, capsule type, bridge type load cell sensor, cylinder type load cell sensor and so on.
Operation method of detection:
1: The weighing sensor load cell manufacturer provides the sensor weighing load cell output sensitivity and power supply voltage. We detect the sensor weigh load cell output signal according to these two parameters. The strain gauge load cell weigh sensor outputs analog signal millivolt voltage.
For example, the output sensitivity of the sensor weighing load cell is 2.0mv/v, and the power supply voltage is dc10v. The two parameters can provide us with a linear relationship that the working voltage of the weighing sensor load cell excitation needs dc10v, and the output signal of the sensor corresponds to 2.0MV output for every 1V excitation voltage.
For example, if the full scale of the sensor weighing load cell is 50kg, give the sensor dc10v voltage and output 20mV at full scale. According to this relationship, we measure the output signal of the sensor with the MV gear of the multimeter. The no-load output of the sensor is 0 mV, which is normal, greater than this value, but close to this value, the value change is that the sensor has zero drift. If the value is large, the sensor weighing load cell is damaged or the internal bridge is a circuit, and the bridge arm resistance is asymmetric.
2: According to the weighing sensor load cell parameters, input resistance and output resistance provided by the factory, judge whether the sensor strain gauge is damaged. The input and output resistance values of weighing load cell sensors vary from manufacturer to manufacturer.
So this should be tested according to the manufacturer's label. Use the ohm gear of the multimeter to detect the resistance of the power supply and the power supply ground, and the resistance of the signal line and the signal ground. If the resistance value is larger than the factory resistance value, the sensor has been overloaded and the strain gauge is deformed. If the resistance value is infinite, the sensor strain gauge is seriously damaged and cannot be repaired.
3. Because the lead of the sensor weigh load cell is often broken in the process of using, and the outer layer of the sheath wire is intact, we visually check the integrity of the weighing load cell sensor wire, and we use the ohm gear of the multimeter to detect whether the sensor wire is on or off. If the resistance is infinite, the fracture is determined. If the resistance changes, the contact is poor.