How to judge the quality of the belt scale sensor? Deep analysis of key test items

How to judge the quality of the belt scale sensor? Deep analysis of key test items

I. Basic Static Detection: Parameters and Insulation

• Resistance Measurement: Disconnect all wiring, and use a high-precision multimeter to measure the input terminals (usually marked as EXC+, EXC-) and output terminals (SIG+, SIG-) of the sensor. Compare with the nominal values provided by the manufacturer (common input resistance is about 3800Ω ± 10Ω, output resistance is about 350Ω ± 3Ω). Significant deviations usually indicate damage to internal strain gauges or wiring.
• Insulation Resistance Test: Use a megohmmeter (500VDC gear). Measure the insulation resistance between the input and output terminals of the sensor bridge and the sensor body (housing/ground terminal) respectively. The qualified standard usually requires insulation resistance ≥ 5000 MΩ (or higher standards from the manufacturer). Insufficient insulation (especially down to several tens of MΩ) is often caused by internal moisture, contamination, or electrical isolation damage, which is very likely to cause unstable signals or interference.

II. Dynamic Signal Analysis: Zero Point and Sensitivity

• Zero Output Detection (No Load): After confirming that the belt scale is installed normally, the belt runs stably without material, connect the instrument. Record the zero load value displayed by the instrument (unit: mV/V or instrument scale value). Compare with the initial stable value or the manufacturer's specified value. Zero drift beyond the allowable range (such as ±0.1% FS or as specified by the manufacturer) may indicate sensor overload fatigue, temperature compensation failure, or structural deformation.
• Sensitivity and Linearity Check: If conditions permit, conduct a simple dynamic weight testing. Place standard weights (such as chain weights, hanging weights) at known belt positions and let the weights pass through the weighing area completely. Observe the difference between the instrument display value and the actual value. Significant errors (such as >0.5%) or abnormal signal fluctuations (毛刺，jumps) strongly indicate sensor sensitivity degradation and nonlinearity or core component damage. This step can effectively expose hidden dangers that are difficult to detect only by static testing.

III. Physical State and Installation Verification

• External and Mechanical Inspection: Carefully check whether the sensor itself has obvious physical damage: such as shell cracking, severe corrosion, and obvious deformation of the force-bearing part. Check whether the contact surface between the sensor and its installation base (weighing idler) is flat, clean, and free of foreign matter. Ensure that all installation bolts are tightened according to the manufacturer's specified torque, without loosening or over-tightening leading to strain deformation.
• Load Transfer Inspection: The core is to confirm that the material weight effectively acts on the sensor. Observe whether the heights of the weighing idler and its adjacent idlers are level (can be checked with a ruler or tension line). Check whether the idlers in the weighing area rotate flexibly, without dead spots, material sticking, or excessive wear. Check whether the belt runs smoothly in the weighing section, without deviation, slipping, or abnormal tension changes. Any mechanical problem that hinders the effective transmission of gravity to the sensor will manifest as a sensor "failure".