Common Faults And Treatment Methods Of Electronic Balance


Common Faults And Treatment Methods Of Electronic Balance

1.It cannot return to zero after the weighing object is removed

Check whether the sensor output signal value is within the standard (A/D total amplification code/use inner code range/bottom code range). If the signal value is not within the standard, adjust the sensor's adjustable resistance and adjust the signal value to within the standard. If you can’t compensate, please check whether there is a problem with the sensor. Under the condition of ensuring that the sensor output is normal (the scale body is stable), lock the instrument failure. Generally, there is a problem with the amplifier circuit and A/D conversion circuit. Then judge the test and analysis one by one according to the circuit principle. Finally solve the problem.

2.Display garbled

Remove the original display circuit and replace it with a normal display circuit to see if it is normal. If the display is normal, it means that there is a problem with the display circuit. If it is not normal, check whether the drive circuit is faulty, and finally check whether the display output pin of the processor is in a reasonable output range.

3.Failure analysis of inaccurate weighing

Observe whether the internal code value is stable, whether there is friction in various parts of the sensor, whether the stabilized voltage supply is stable, whether the operational amplifier circuit is normal, and use a weight to test whether the four-foot scale of the weighing pan is even. Follow the instructions in the manual for further local analysis or weight calibration of the instrument.

4.Failure to boot

First determine whether the problem is not caused by the fuse, power switch, power cord and voltage switch, and check whether the transformer has AC voltage input and AC output. If the meter has a battery, remove the battery and turn it on with AC power to see if it is caused by insufficient battery voltage. Secondly, check whether the rectifier circuit, voltage stabilizing circuit and display drive circuit are abnormal. If these are all correct, check whether the processor and auxiliary circuits are burned out.

5.The buttons don't work well

First replace the new button to test. If the function of the new button is normal, it can be judged that the button is in poor contact, and measure whether the circuit between the button and the CPU is open or soldered. Check whether the button support has bad contact. Measure whether there is a short circuit or open circuit on the diodes and resistances on the button and the CPU circuit.

6.Pointer jump

When the beam is lifted, if the distance between the blade of the fulcrum knife and the knife pad is not equal, the pointer will jump when the balance is turned on. You can loosen the screw in front of the left arm of the horizontal bracket, and then adjust the small pillar by twisting it by hand. Until the pointer no longer jumps.

7.It can't be fully loaded

Similar to the situation where the zero return is impossible, most of it may be due to changes in the small signal input range. According to the method that cannot be returned to zero, if the problem cannot be found, first check whether the power supply and A/D circuit are normal, and then check the sensor output.

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