The error range of Xi'an Shenghongchuang high-precision weighing sensors is usually ±0.02%FS to ±0.05%FS, and the recommended calibration interval is once every 6 to 12 months, which should be determined based on frequency of use, environmental stability, and metrology requirements.

This range directly affects whether the measurement results can be used for quality control, trade settlement, or process closed-loop control. To determine suitability, priority should be given to confirming whether there are severe temperature fluctuations, mechanical vibration, overload shock, or corrosive media on site—these factors are more likely than nominal accuracy to cause the actual error to exceed the limit.

What is FS? Why is error expressed as “%FS” instead of “% of reading”?

%FS refers to “percentage of full scale,” meaning the error value is calculated based on the maximum measurable load of the sensor. For example, for a sensor with a 1-ton range, ±0.02%FS corresponds to a fixed error band of ±0.2kg, and whether the current weight is 10kg or 900kg, the upper limit of this deviation remains unchanged.

This differs from “% of reading”: the latter changes linearly with the current measured value, being more stringent at small ranges and more lenient at large ranges. Industrial weighing mostly uses the %FS designation because it facilitates system-level error allocation and safety boundary setting.

Whether higher accuracy is needed mainly depends on the downstream application—if it is used for batching control and the formula tolerance is less than 0.1%, then repeatability and temperature drift should be emphasized rather than only the nominal FS error.

Why is the calibration interval not uniformly specified, but instead recommended as 6–12 months?

There is no mandatory uniform time limit for the calibration interval, because the actual drift rate depends on installation condition, load characteristics, and environment. For example, a sensor used for continuous weighing in a constant-temperature clean workshop may still maintain ±0.03%FS after 12 months; while the same model used in an open-air yard with frequent starts and stops, exposed to sun and rain, may show a deviation of ±0.08%FS after 6 months.

A more common practice is: conduct one reinspection 1 month after initial commissioning to observe the trend; if the cumulative drift is <0.02%FS/month, it can be extended to 12 months; if the monthly drift is >0.03%FS, it should be shortened to 3 months and the installation foundation or wiring issues should be investigated.

What truly affects the interval is not time itself, but the “number of stress cycles” and the “intensity of environmental disturbances” under the sensor’s operating conditions.

In which situations must calibration be performed in advance rather than waiting until the interval expires?

Trigger scenarios	Core causes	Risk Warning
Replace the mounting base or fastening bolts	Changes in mechanical preload cause zero point and linearity drift	May introduce hidden errors above 0.1%FS, which cannot be eliminated through software zero adjustment
Experienced over-range impact shock (such as material drop impact)	Microscopic plastic deformation of the elastic body is irreversible	Even if there is no visible damage, repeatability and hysteresis indicators may deteriorate
Ambient temperature difference exceeds 40℃ and no temperature compensation is applied	Thermal expansion and contraction of metal materials alter the strain transmission path	Zero drift often reaches 0.05%FS/10℃, far exceeding the nominal accuracy value

Under the above three situations, whether immediate calibration is required depends on whether trade handover, quality arbitration, or automatic control shutdown thresholds are involved—if they are involved, calibration must be completed before continued use.

Among the error sources of high-precision weighing sensors, which can be eliminated by calibration and which cannot?

Calibration can only correct systematic deviations, such as zero-point drift, sensitivity coefficient deviation, and linear fitting error. However, it cannot improve random error sources, including transient temperature response lag, signal jitter caused by electromagnetic interference, slight variation in cable contact resistance, and eccentric load error caused by non-parallel installation surfaces.

If the goal is long-term stability better than ±0.03%FS, periodic calibration alone is not enough. It is also necessary to simultaneously control the installation process (such as using spherical washers), shielded cable routing, install temperature compensation modules, and avoid placing the sensor at air-conditioning outlets or in locations exposed to direct sunlight.

Whether this step should be moved forward depends on the final application’s requirements for “process stability,” rather than simply on the nominal accuracy grade.

What differences are there in calibration methods and equipment requirements for sensors of different accuracy grades?

Accuracy Class	Typical error range	Minimum requirements for calibration equipment	Whether on-site calibration is recommended
C3 class (general industrial use)	±0.02%FS	0.005%FS standard weight set + 6½-digit digital multimeter	Can be implemented on site, requiring 2 hours of constant-temperature stabilization
C4 class (high precision)	±0.01%FS	0.001%FS standard weights + dedicated weighing instrument + anti-vibration platform	Recommended to return to the factory or send to a metrology institute, as environmental variables are difficult to control on site
C5 class (laboratory grade)	±0.005%FS	National secondary standard machine + air buoyancy correction + real-time temperature and humidity monitoring	On-site calibration is not possible and must be carried out by a professional metrology institution

When choosing which grade to use, you should not only look at the parameter table, but should calculate the error chain of the entire weighing system—from the sensor, wiring, instrument A/D conversion, temperature compensation algorithm to installation structure rigidity, any weak link will reduce the overall performance.

Checklist and action recommendations

• If the weighing result is used for internal process reference and the tolerance is >0.5%, then a Class C3 sensor with a 12-month calibration interval is usually sufficient.
• If there is obvious vibration on site, a temperature difference >30℃, or overload shock has occurred, then even if calibration is not yet due, priority should still be given to checking zero-point stability and repeatability test data.
• If the downstream system requires automatic alarm or shutdown, and the threshold is set within ±0.1%, then the sensor’s measured temperature drift and hysteresis indicators under the target operating conditions must be verified, rather than relying only on the factory report.
• If mechanical installation calibration has not yet been completed (such as corner error <0.05%FS), then advance calibration has limited significance, and installation foundation issues should be resolved first.

Recommended first step: under the current operating condition, continuously record the no-load zero point and full-scale output values for 72 hours, and plot a trend chart; if the single-day fluctuation is >0.02%FS, priority should be given to investigating grounding, power interference, or foundation settlement issues before deciding whether to initiate the calibration process.