Device profile

A device profile is the reusable template describing how a class of devices maps raw values to engineering values.

• A descriptor is one measurement-point key with unit, precision and a value transform (identity, linear, lookup table, expression, or enum).
• The platform never guesses units: a unit exists only when the descriptor declares it.
• Descriptors are versioned; re-calibration never rewrites stored history.
• A profile may bind a rule chain; devices using it execute that chain unless they override the binding.

A profile is the point table; a connector instance holds the per-device connection parameters. At dispatch the instance overrides are merged over the profile template.