Application precautions and foundations for calibration of weighing scales without weights

In the heavy industry sector, ground scales are key measurement equipment, and their accuracy is directly related to trade settlement, production control, and other crucial aspects. Weightless calibration technology is widely applied in some scenarios due to its advantage of eliminating the need to repeatedly move heavy calibration weights, thus saving time and labor costs. However, there are inherent risks during prolonged use, as subtle changes in the ground foundation, sensor installation position, and the weighbridge itself can cascade and impact the scale's accuracy. A positive and negative analysis must be conducted to formulate corresponding strategies.

I. Core Precautions for Weightless Calibration

Weightless calibration is convenient (it is typically based on "simulated load calibration" or relies on sensor wiring parameters calculation), but it is essentially an indirect simulation of the actual load. Key points must be strictly controlled to prevent accuracy deviation.

1. Prerequisite Verification: Ensuring the Foundation is Effective

• Initial Status Validation:

  • Before performing weightless calibration, it must first be confirmed that the weighbridge is free of historical faults (such as sensor damage, wiring box getting damp). Furthermore, the calibration must be based on valid data from a previous mass calibration conducted within the last 3 months. If the ground scale has not undergone mass calibration for a long time, cumulative errors such as sensor linearity errors and weighbridge deformation will cause the weightless calibration results to be inaccurate.

• Environmental Stability Control:

  • Calibration must be carried out in a stable ambient temperature (recommended $15-25^circ C$) and humidity (relative humidity $leq 85%$), avoiding air drafts, vibration, and interference. Significant temperature changes cause the sensor's elastic body to thermally expand and contract, directly affecting the output signal accuracy, and at this time, the compensation algorithm used in weightless calibration cannot accurately correct the error.

• Software and Access Control:

  • Only qualified technical personnel should operate the calibration software, and the original calibration parameters must be backed up (such as sensor sensitivity, linearity, corner error correction values). Non-professional personnel are prohibited from modifying core parameters such as the "calibration coefficient" and "capacity range" to prevent operational errors leading to massive data failure.