A silo weighing system is a mechanical structure with load cells attached, not a scale that happens to be large. Most accuracy problems come from the structure, and no cell specification can compensate for them.
Restraint is the main enemy
Any pipe, conduit or stairway rigidly connected to the silo bypasses load through an alternative path. Flexible connections on every pipe, with the flexibility axis aligned to the direction of movement, are mandatory. Check that the flexible section is not installed under tension; a stretched bellows transmits force.
Thermal movement
A steel silo 10 m tall moves several millimetres between day and night. Cells must allow that movement without side load: rocker pin or self-aligning canister mounts, with the load direction vertical and free to tilt. Bolting a cell down rigidly converts thermal movement into side load and zero drift.
Wind and seismic
Lateral restraint should be provided by separate stays with clearance, not by the load cells. Design the stays so they take horizontal load without vertical force, and check the clearance after any settlement.
Commissioning
Load the silo with a known quantity, compare with the indicated weight, and repeat at three fill levels. A consistent percentage error points to calibration; a varying error points to restraint or to a cell carrying unequal share.
Kevin Huang