​Steps for electronic floor scale repair

Steps for electronic floor scale repair
 With more than 20 years of experience in weighing instrument verification, the author summarizes the trilogy (12 words) method.

 Step 1 diagnosis: follow the line, measure on and off. Determine if the problem is caused by the breakdown of fuses, power switches, power cords, voltage switches, solder joints, and electronic components (voltage regulators, sensors, etc.). Ninety percent of problems can be detected. Of course, if the voltage block and electrical block of the multimeter are used again, check the ac110/220 and AC18V parameters at the input end of the transformer and the output end of the transformer, measure the battery voltage and the output signal value parameters of the sensor, etc. More than 95 percent of the problems can be detected.

 Step 2 treatment: weld carefully and change simply. Careful welding is to pay attention to the high temperature, long time, will be integrated blocks, sensors and other electronic components damage. Simple change is to point to power line, fuse, power switch, voltage switch, protective capacitor, voltage regulator tube, single secondary tube and other inexpensive accessories to change. Replace sensors if they are cheap and easy to buy.

 Step 3 verification: make judgment according to the procedure. It refers to the  verification according to the national metrological verification regulations jjg539-1997 and determines whether it is qualified.

 Electronic floor scale repair method

 First, the most important thing is to find, analyze, and determine the location of the ault. The fastest and easiest way to do this is to use a simulator. The specific method is as follows: firstly, unplug the signal data cable on the back of the weighing display instrument, insert the output cable plug of the simulator into the corresponding part of the signal data cable, and then observe the working condition of the instrument after connecting the power. If the work is normal (especially the zero display is normal), it can be judged that the weighing display instrument is normal and the fault is in other parts.

 On the contrary, if the work is abnormal (such as no display or zero flicker,  etc.), the fault can be basically determined in the power supply part of the front end or in the weighing display instrument. The problems of supply voltage and frequency are easy to check and judge with multimeter. This method is generally qualitative judgment, not quantitative analysis. In fact, it is unnecessary to use oscilloscope, weight and multimeter for quantitative analysis in most cases. If the display instrument is normal, but the error of electronic floor scale indication exceeds the requirements of the procedure or the error of partial load test exceeds the requirements of the procedure and the repeatability test exceeds the requirements of the procedure, this method cannot be used to determine the fault. In this case, the simplest method is to use the simulator to carry out simulation verification. If necessary, standard weights will be used to carry out demonstration error verification and discrimination test, and oscilloscope and multimeter will be used for measurement determination. Usually, weighing display instrument has the probability of failure is very small, under normal circumstances should first  appearance inspection of each component of electronic balance, key check whether cable short circuit or wire, cable box, shielding are in good condition, sensor for damage, limit device is loose, foundation levelness whether changes, etc.