The accuracy of the weighbridge is not good, which will inevitably affect the accuracy and reliability of the measurement results. This problem should be repaired in time.

The adjustment of the weighing accuracy of the weighbridge is different from the adjustment of the weighing accuracy of other table scales. It is not to adjust the support, weight and force point knife, but to adjust the weight of the weight and change the corresponding position of the measuring scale notch on the scale. Because the structure of the weighbridge determines that the main weight (also known as the large weight) has a large adjustment cavity inside, increasing or reducing the filling in its adjustment cavity can change the quality of the main weight. As is known to all, the measuring lever on the scale of scale weight only has a fulcrum and two key knives. The weight is equivalent to a moving force point. Adjusting the weight's mass is actually equivalent to adjusting the support distance of the measuring lever, thus changing the force arm of the measuring lever, and achieving the purpose of adjusting the accuracy of the weighing.

The accuracy of the card value of the main scale of the weighbridge is inaccurate or out of tolerance. There are mainly the following repair methods:

（1） The adjustment method for the indication error to increase or decrease regularly with the scale size

1. For the adjustment and repair of this problem, first of all, select a suitable scale notch as the adjustment point, and adjust the zero position of the floor scale under the no-load condition, that is, make the floor scale in the empty balance state.

2. Move the main weight to the indicated value of the selected notch in 1, and place a weight equal to the indicated value of the selected notch in 1 on the platform of the weighbridge.

3. Open the stopper and allow the measuring lever to swing freely. According to the indication error of the weighbridge, increase or decrease the mass of the filler (lead, etc.) in the weighbridge adjustment cavity to keep the weighbridge in balance.

4. Remove all weights from the floor scale platform and readjust the balance of the empty scale.

5. Then place the weight at the indicated value of the selected notch, put a weight equal to the indicated value of the notch on the table, and open the switch stopper. If the error is within the allowable error, it means that the adjustment is qualified; If the error does not meet the tolerance requirements, the above process shall be repeated until the error of the selected notch indication is qualified. Of course, the final one is qualified only after passing the test on other notches. In short, the quality adjustment of the weight should be repeated several times before it can be adjusted properly. It should be patient, careful and not impatient.

（2） Most of the main scale indications are qualified, and only a few of them are out of tolerance

There are two ways to adjust and repair this situation.

1. If the indication value of individual notches is more than the same, the method of adjusting the mass of the main weight can be adopted to make the weighing accuracy of the weighbridge qualified. For example, there is a floor scale with a total weight of 10t. During the verification, except for the 9t and 10t notches, the accuracy of other notches is qualified and the error is positive. The error is+10.5kg at 9t and+12kg at 10t. During adjustment and repair, the mass of some main weights can be increased, so that the indicated value of the scale can be reduced by about 0.5kg per ton, so that the qualified notch will develop towards negative or positive difference, but it is still within the tolerance range. At this time, the indication error at 9t is reduced to 6kg, while the indication error at 10t is reduced to 7kg. At this time, the indication error of all scale notches is within the acceptable range.

2. If the indication error of individual notches exceeds the tolerance too much, it is obviously impossible to achieve the purpose by using the above method. This situation shows that there is a large error in the slot distance between the corresponding out-of-tolerance slots of the main scale. During adjustment and repair, necessary repair shall be carried out for the out-of-tolerance notch, and the unqualified notch spacing shall be adjusted. During collective adjustment, use a suitable file to file one side of the notch. If the notch indication is positive error, the notch close to the collimator should be rubbed; If the notch indication is negative error, file the notch on the side near the fulcrum knife direction. Force the notch to move in the direction after rubbing, so that the indication error of the out-of-tolerance notch is qualified. However, no matter which direction the file is repaired and the notch is moved, it is necessary to ensure that the repaired notch fits closely with the clamping teeth of the main weight, and there is no looseness. Otherwise, it will bring variable fault to the weighbridge.

（3） Repair methods for most of the out-of-tolerance errors of the scale notch indication regardless of the scale size

First of all, we should eliminate the impact of volatile reasons. On the premise that the variability of the scale is qualified, it indicates that the dividing distance of the main scale notch of the secondary floor scale is uneven. The best way to repair such faults is to remove the tooth bar on the main scale and replace it with a new tooth bar of the same specification and model. For the weighbridge after the new tooth bar is replaced, all the indicated values shall be verified and tested again, and the weight quality shall be adjusted properly. If we do not change the scale tooth bar during the adjustment and repair, we still use a file to repair the notches of the main scale card. Not only do we file too many notches, but also it is easy to cause the notches to be different in width and depth. It is difficult to ensure their parallelism, affect the adjustment effect, and achieve the purpose of qualification.