---
source_files:
  - DataPRO/Modules/DatabaseImporter/DatabaseImport/DASConcepts/Test.Module.Channel.Sensor.SensorUnits.cs
  - DataPRO/Modules/DatabaseImporter/DatabaseImport/DASConcepts/Test.Module.Channel.Sensor.Bridge.cs
  - DataPRO/Modules/DatabaseImporter/DatabaseImport/DASConcepts/DigitalInputScaleMultiplier.cs
  - DataPRO/Modules/DatabaseImporter/DatabaseImport/DASConcepts/LinearizationFormula.cs
generated_at: "2026-04-16T04:29:46.893362+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "50ada406a17a3727"
---

# Documentation: Sensor & Linearization Concepts Module

## 1. Purpose

This module defines core data structures and enumerations used to represent sensor configuration and signal linearization behavior within the DatabaseImporter subsystem of the DTS DataPRO system. It provides strongly-typed representations of sensor sensitivity units (`SensUnits`), bridge configurations (`BridgeType`), digital input scaling (`DigitalInputScaleMultiplier`), and various linearization formulae (`LinearizationFormula`)—all derived from legacy database serialization formats. These constructs enable consistent interpretation and persistence of sensor metadata during database import operations, bridging historical DTS-specific formats with modern .NET type safety.

## 2. Public Interface

### `Test.Module.Channel.Sensor.SensUnits` (enum)

- **Definition**: `public enum SensUnits`
- **Values**:
  - `NONE = 0` → Polynomial sensor with no sensitivity units.
  - `mV = 1` → Sensitivity in millivolts at full-scale (Capacity EU).
  - `mVperV = 2` → Excitation-proportional sensitivity in mV/V at full-scale.
  - `mVperVperEU = 3` → Excitation-proportional sensitivity per engineering unit (mV/V/EU).
  - `mVperEU = 4` → Sensitivity in mV per engineering unit.
- **Behavior**: Encodes the unit type for sensor sensitivity; used to interpret sensitivity values in configuration.

### `Test.Module.Channel.Sensor.BridgeType` (enum)

- **Definition**: `public enum BridgeType`
- **Values** (bitmask flags):
  - `IEPE = 1 << 0` → IEPE (Integrated Electronics Piezo Electric) sensor setup.
  - `QuarterBridge = 1 << 1` → Quarter-bridge configuration.
  - `HalfBridge = 1 << 2` → Half-bridge configuration.
  - `FullBridge = 1 << 3` → Full-bridge configuration.
  - `DigitalInput = 1 << 4` → Digital input mode.
  - `SQUIB = 1 << 5` → Squib (pyrotechnic) output setup.
  - `TOMDigital = 1 << 6` → TOM (Test Output Module) digital output.
  - `HalfBridge_SigPlus = 1 << 7` → G5 half-bridge with signal-plus wiring.
- **Behavior**: Represents physical bridge/wiring topology; supports bitwise combinations.

### `DigitalInputScaleMultiplier` (class)

- **Definition**: `public class DigitalInputScaleMultiplier`
- **Properties**:
  - `Form`: `Forms` enum; currently only `ArbitraryLowAndHigh` supported.
  - `DefaultValue`: `double`; value displayed when digital input = 0 (OFF).
  - `ActiveValue`: `double`; value displayed when digital input = 1 (ON); defaults to `1.0`.
- **Constructors**:
  - `DigitalInputScaleMultiplier()` → Initializes `DefaultValue = 0.0`.
  - `DigitalInputScaleMultiplier(DigitalInputScaleMultiplier copy)` → Copy constructor.
- **Methods**:
  - `void FromDbSerializeString(string s)` → Parses serialized string (e.g., `"ArbitraryLowAndHigh,0.0,5.0"`) into object state.
    - Throws `NotSupportedException` on malformed input or unsupported format.
    - Uses `InvariantCulture` for numeric parsing.

### `LinearizationFormula` (class)

- **Definition**: `public class LinearizationFormula`
- **Properties**:
  - `NonLinearStyle`: `NonLinearStyles` (not defined in provided files; inferred from usage).
  - `PolynomialSensitivity`: `double`; sensitivity for polynomial models.
  - `LinearizationExponent`: `double`; exponent in power-law models.
  - `MMPerV`: `double`; millimeters per volt (note: comment indicates variable name is inaccurate).
  - `MVAt0MM`: `double`; millivolts at zero millimeters.
  - `Slope`, `Intercept`: `double`; linear model parameters.
  - `CalibrationFactor`: `double`; calibration coefficient.
  - `ZeroPositionIntercept`: `double`; intercept at zero position.
  - `UsemVOverVForPolys`: `bool`; flag for polynomial unit preference (default `true`).
- **Constructors**:
  - `LinearizationFormula()` → Initializes default state (e.g., `_coefficients = [0,0,0,0]`, `_exponents = [0,1,2,3]`).
  - `LinearizationFormula(LinearizationFormula copy)` → Copy constructor.
- **Methods**:
  - `void MarkValid(bool bValid)` → Sets internal `_bIsValid` flag (no getter exposed).
  - `void FromSerializeString(string s, CultureInfo culture)` → Parses serialized format: `<Style>_<params>`.
    - Supports styles: `IRTraccDiagnosticsZero`, `IRTraccManual`, `IRTraccZeroMMmV`, `Polynomial`, `IRTraccAverageOverTime`, `IRTraccCalFactor`.
    - Throws `NotSupportedException` for unknown styles or malformed data.
  - `void FromSerializeString(string s)` → Overload using `InvariantCulture`.
  - Private helper methods (called by `FromSerializeString`):
    - `FromIRTraccCalFactorString`, `FromIRTraccDiagnosticZeroString`, `FromIRTraccManualString`, `FromIRTraccAverageOverTimeString`, `FromIRTraccZeroMMmVString`, `FromPolynomialString`  
      → Parse style-specific parameter strings (e.g., `"Slope x Exponent x Intercept"`).

## 3. Invariants

- **`SensUnits`**:
  - Values are mutually exclusive and non-overlapping (no bitwise combinations).
  - `NONE` (0) is reserved for polynomial sensors lacking sensitivity units.

- **`BridgeType`**:
  - Values are bitmask flags; multiple types may be combined via bitwise OR.
  - Only one physical bridge type (e.g., `QuarterBridge`, `HalfBridge`, `FullBridge`) should be active per sensor, though combinations like `DigitalInput | TOMDigital` may be valid.

- **`DigitalInputScaleMultiplier`**:
  - `Form` must be `ArbitraryLowAndHigh`; no other forms are implemented.
  - `DefaultValue` and `ActiveValue` must be parseable as `double`; invalid values throw `NotSupportedException`.

- **`LinearizationFormula`**:
  - `_bIsValid` is set only by `FromSerializeString` (via `MarkValid` internally); no public validation method exists.
  - `FromSerializeString` expects format `<Style>_<param_string>`; parsing fails if tokens are missing or malformed.
  - Polynomial parsing (`FromPolynomialString`) has ambiguous behavior: if a token lacks `'x'`, it may be interpreted as a special key (`"S"` or `"mV"`) instead of coefficient/exponent.

## 4. Dependencies

- **Internal Dependencies**:
  - Relies on `Test.Module.Channel.Sensor` being defined elsewhere (via `partial class` and `//*** see ... ***` comments).
  - `NonLinearStyles` enum is referenced but not defined in provided files; must be declared in another file (likely `DASConcepts/NonLinearStyles.cs`).
  - Uses `System.ComponentModel.DescriptionAttribute` for enum metadata (not used in logic, likely for UI).

- **External Dependencies**:
  - `System` (core types, `CultureInfo`, `double`, `List<T>`, `string`).
  - `System.Globalization` (`InvariantCulture`, `NumberStyles`).

- **Depended Upon By**:
  - Database import logic (e.g., parsing sensor configuration from legacy DB strings).
  - UI components (via `DescriptionAttribute` for display names).
  - Serialization/deserialization layers for sensor metadata.

## 5. Gotchas

- **`MMPerV` naming is misleading**: Comment explicitly states *"THIS IS MM/V, (UI has already been updated, we need to update the variable name)"*—the variable name does not match its meaning (millimeters per volt, not millivolts per volt).
- **`_bIsValid` is internal-only**: No public `IsValid()` method is exposed despite the private `_bIsValid` field and commented-out `IsValid()` method.
- **Polynomial parsing ambiguity**: In `FromPolynomialString`, tokens without `'x'` are treated as special keys (`"S"`/`"mV"`), but tokens with `'x'` but only one part (e.g., `"2"`) fall through to `PolynomialSensitivity` assignment—this may cause silent misinterpretation.
- **`DigitalInputScaleMultiplier` ignores null/empty input**: `FromDbSerializeString(null)` returns silently (with comment `//FIXME is this the right thing to do?`), potentially masking errors.
- **`BridgeType` values use bit shifts**: While designed for bitwise combination, the enum is not marked `[Flags]`, so tools may not display combined values intuitively.
- **Culture sensitivity**: All numeric parsing uses `InvariantCulture`, but `FromDbSerializeString` in `DigitalInputScaleMultiplier` splits on `CultureInfo.InvariantCulture.TextInfo.ListSeparator` (typically `','`), which may conflict with decimal separators in some locales if not handled consistently upstream.
- **No validation of polynomial coefficients/exponents**: `FromPolynomialString` does not enforce non-empty lists or valid exponents (e.g., negative exponents may be allowed).