FA-93599 / Solar tracker geometry / Member archive

Torque-tube inclinometer rotation: calibration offset sign · case 04

Calibration doubles the mounting error instead of removing it.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

ax (across-axis) and az (normal) are gravity components in g. The magnitude must be within [0.8, 1.2] g, else [None, 'fault']. Rotation = atan2(ax, az) in degrees, negated for a sensor mounted on the west side, then minus the calibration offset, normalised to (-180, 180]. Return [angle rounded 2, 'ok'].

Why this case matters

Single-axis and dual-axis solar trackers turn a sun direction into actuator commands; a sign, frame or limit mistake points a whole plant away from the sun or into a mechanical stop.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: calibration offset sign	`[-175.0, "ok"]`	`[175.0, "ok"]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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