Floor scale sensor daily use failure analysis

Weighbridge Weighing Sensor Fault Case Analysis Weighing sensor is the most critical component in the weighbridge. It acts to transmit gravity into an electrical signal. If the load cell fails, it will cause errors in the conversion, which directly affects the normal of the weighbridge. jobs. Failure of the load cell may result in large scale error, zero return, large offset error, and poor repeatability. Finding a load cell failure can be done by:

Use a multimeter to check the resistance between the positive (+EX) and negative (-EX) terminals in the junction box (measured on the signal post leading to the meter in the junction box) with a resistance of approximately 400D/sensor. Use a multimeter to measure the resistance between the positive output (+Si) and the negative output (-Si) at the total output. The resistance is approximately 2500Q/section (Note). If the resistance is found to be incorrect, press Next to find it.
Note: The cross section is the longitudinal direction of the vertical weighing platform, the face of each pair of sensors. That is, a section generally has a pair of sensors, such as a 30t weighbridge with 4 sensors, divided into two sections, the number of sections is 2.
The sensor is disconnected one by one, and the impedance between the positive and negative excitation terminals or the positive and negative output terminals is measured by the method of the above (1) to detect the damaged sensor. If there is no problem with this step, press the step to continue searching.
Place the weights on each section of the weighing platform in turn. If the indication of the section is found to be incorrect, place the weight on the sensor angle of this section (pressure angle) to detect the bad sensor and replace the sensor.
Or disconnect the +Si, -Si end of a sensor to measure the resistance value when it is not energized. It should be around 350Q. Under the condition of power-on, measure the DC voltage at both ends and set the sensor capacity to K. The actual force it receives is F, if the 8142 meter is used, the voltage value should be: 12.5X2F/K (mV).
Case:
Fault phenomenon: When a 30t electronic platform scale is displayed, the timing is negative and the weighing error is large.
Fault analysis: a, the mechanical structure is faulty; b, the sensor is damaged.
Troubleshooting: Using a 3t forklift to press the four corners, it was found that one of the corners was particularly large. It is estimated that the sensor has failed. Disconnect the sensor leads in the junction box, and measure the difference between the input and output resistance with a multimeter. Focusing on the sensor that measures the larger angle, the input resistance changes greatly (normal value is 382 Q±4Q). If the sensor is replaced, the fault is eliminated.