Why can't I adjust the angle difference and segment difference of the weighing scale?

I. Mechanical Structure: Hidden Dangers in the Integrity of the Weighbridge and Components

The integrity of the mechanical structure is the foundation for ensuring weighing accuracy. Problems in this area are particularly pronounced in large-tonnage ground scales.

1. Weighbridge Deformation and Position Shift Problems

The connection points of multi-section weighbridges are areas of heavy load concentration. For example, a 100-ton, three-section ground scale can become prone to soil accumulation and corrosion on the butt plates due to rainwater seepage, causing uneven force reception. This leads to common issues where the test vehicle's weight deviation exceeds 100kg between adjacent sections; other cases include the weighbridge bottom plate or side plate being subjected to uneven force, which causes over-turning angle errors to recur after correction, with an accuracy deviation of 50-60kg. Additionally, the position shift caused by thermal expansion and contraction of the pure steel structure weighbridge (e.g., a 12-20mm shift when the temperature changes by $18^circ C$) can also exacerbate the error.

2. Limit Device and Anti-Interference Failure

The limit gap is a detail that is often overlooked. If the limit device is jammed or the gap is too small (the standard is typically maintained at 5-10mm), it will restrict the weighbridge from deforming, causing the sensor to receive uneven force. If the material stacked on the weighbridge contacts the limit block, it will alter the support distribution, leading to the recurring presence of corner errors and even damage to the sensor. Regular inspection and cleanup of debris from the bottom of the weighbridge at the limit position must be carried out to completely eliminate existing 10kg corner errors.

II. Core Components: Performance Failure of the Sensor and Wiring System

The sensor and wiring box act as the core for signal acquisition and processing. Any abnormality in their performance can directly lead to weighing failure.

1. Multi-Sensor Failure

Sensor differences are a primary source of corner errors. When a single sensor has an error of 30-50kg, there is a high probability of sensor damage—long-term overload, lightning strikes, or impact can cause elastic body deformation, leading to signal output degradation. A more hidden problem is sensor mismatch: if mixed use of sensors with different creep characteristics (e.g., $2.0$ and $3.0$ creep grades) is allowed, or if installation unevenness leads to inconsistent force application, it will cause the segment error to continue even after the wiring box is connected and the system is calibrated. For example, one southern manufacturer stated that after 2 sensors were virtually connected (i.e., loosely supported) on a weighbridge, the segment error persisted until padding was used to eliminate the fault.

2. Hidden Dangers in Wiring Connections

The wiring box getting damp, terminal oxidation, or virtual connection of the wiring can cause signal drift. In a case study, after water entered the wiring box, the instrument reading fluctuated frequently. Although the reading stabilized after internal moisture was dried out, the failure could recur due to corrosion of the internal circuit board or vibration loosening the sensor wiring, causing an intermittent zero point or signal deviation. It is worth noting that if a new sensor is replaced without re-calibrating the corner weights via the wiring box, a situation of "old faults uneliminated, new problems arising" may occur.