---
source_files:
  - Common/DTS.Common.DAS.Concepts/Test/Module/Channel/Sensor/SensorUnits.cs
  - Common/DTS.Common.DAS.Concepts/Test/Module/Channel/Sensor/ExcitationVoltage.cs
generated_at: "2026-04-16T02:04:34.963354+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "00bbefe8072cdb62"
---

# Sensor

## Documentation Page: Sensor Unit and Excitation Voltage Handling in `DTS.Common.DAS.Concepts.Test.Module.Channel.Sensor`

---

### 1. **Purpose**

This module provides supporting infrastructure for sensor channel configuration within the DTS DAS (Data Acquisition System) concepts framework—specifically, it defines the enumeration of sensitivity unit types (`SensUnits`) used to interpret sensor calibration data, and provides utility methods for converting between excitation voltage options and their numeric magnitudes (e.g., 2.0 V, 5.0 V). It exists to standardize how sensor sensitivity and excitation conditions are represented and transformed across the system, enabling consistent scaling and unit conversion for physical measurements.

---

### 2. **Public Interface**

All public members reside within the nested type hierarchy `Test.Module.Channel.Sensor`.

#### **`SensUnits` Enum**
- **Namespace**: `DTS.Common.DAS.Concepts.Test.Module.Channel.Sensor`
- **Definition**:
  ```csharp
  public enum SensUnits
  {
      NONE = 0,
      mV = 1,
      mVperV = 2,
      mVperVperEU = 3,
      mVperEU = 4
  }
  ```
- **Behavior**:
  - Represents the unit types for sensor sensitivity.
  - Each value has a `[Description]` attribute indicating its human-readable form (e.g., `"mV/V/EU"` for `mVperVperEU`).
  - `NONE` indicates a polynomial sensor (no sensitivity unit).
  - Values are mutually exclusive and exhaustive for sensitivity unit specification.

#### **`GetExcitationVoltageMagnitudeFromEnum(ExcitationVoltageOptions.ExcitationVoltageOption target)`**
- **Namespace**: `DTS.Common.DAS.Concepts.Test.Module.Channel.Sensor`
- **Signature**:
  ```csharp
  public static double GetExcitationVoltageMagnitudeFromEnum(ExcitationVoltageOptions.ExcitationVoltageOption target)
  ```
- **Behavior**:
  - Converts a given `ExcitationVoltageOptions.ExcitationVoltageOption` enum value to its associated voltage magnitude (in volts).
  - Uses an internal `VoltageMagnitudeAttributeCoder` (not visible in source but referenced) to decode the magnitude.
  - Throws `ArgumentException` on failure (e.g., invalid enum or missing attribute).

#### **`GetExcitationVoltageEnumFromMagnitude(double magnitude)`**
- **Namespace**: `DTS.Common.DAS.Concepts.Test.Module.Channel.Sensor`
- **Signature**:
  ```csharp
  public static ExcitationVoltageOptions.ExcitationVoltageOption GetExcitationVoltageEnumFromMagnitude(double magnitude)
  ```
- **Behavior**:
  - Converts a numeric voltage magnitude (e.g., `5.0`) to the corresponding `ExcitationVoltageOptions.ExcitationVoltageOption` enum value.
  - Uses `VoltageMagnitudeAttributeCoder.EncodeAttributeValue()` internally.
  - On failure (e.g., magnitude not supported), logs via `APILogger` and returns `ExcitationVoltageOptions.ExcitationVoltageOption.Undefined`.

> **Note**: The `ExcitationVoltageOptions` type and its `VoltageMagnitudeAttribute`/`VoltageMagnitudeAttributeCoder` classes are *referenced* but *not defined* in the provided source files. Their full definitions must be found elsewhere (e.g., in `DTS.Common.Enums` or related files).

---

### 3. **Invariants**

- **`SensUnits` enum values are exhaustive and mutually exclusive** for sensitivity unit specification; no other unit types are defined in this module.
- **`GetExcitationVoltageMagnitudeFromEnum`** requires a valid `ExcitationVoltageOptions.ExcitationVoltageOption` field with a `VoltageMagnitudeAttribute`; otherwise, it throws.
- **`GetExcitationVoltageEnumFromMagnitude`** is *permissive*: it returns `Undefined` on failure instead of throwing, and always logs the failure.
- Voltage magnitudes are assumed to be in **volts (V)**.
- The mapping between enum values and magnitudes is **fixed and pre-defined** (e.g., `Volt5` → `5.0`), and enforced by `VoltageMagnitudeAttribute`.

---

### 4. **Dependencies**

#### **Internal Dependencies (within this module)**:
- `DTS.Common.DAS.Concepts.Test.Module.Channel.Sensor` (nested class hierarchy).
- `System.ComponentModel` (for `[Description]` attributes).
- `DTS.Common.Enums` (contains `ExcitationVoltageOptions` type).
- `DTS.Common.Utilities.Logging` (for `APILogger`).

#### **External Dependencies**:
- `DTS.Common.Enums.ExcitationVoltageOptions` — defines the `ExcitationVoltageOption` enum and `VoltageMagnitudeAttribute` (not included here).
- `DTS.Common.Utilities.AttributeCoder<TEnum, TAttr, TVal>` — base class used by `VoltageMagnitudeAttributeCoder` (not included here).

#### **Dependents**:
- Any code that configures or interprets sensor sensitivity (e.g., calibration, scaling, or unit conversion logic in DAS modules).
- Hardware abstraction layers that set or read excitation voltage settings.

---

### 5. **Gotchas**

- **Incomplete Source**: The `ExcitationVoltageOptions` type and its `VoltageMagnitudeAttribute`/`VoltageMagnitudeAttributeCoder` are *not defined* in the provided files. Their behavior and supported enum values are inferred from usage and comments, but cannot be verified from this source alone.
- **Commented-Out Code**: The `ExcitationVoltageOption` enum and related classes (`VoltageMagnitudeAttribute`, `VoltageMagnitudeAttributeCoder`) are commented out in `ExcitationVoltage.cs`. This suggests possible deprecation or refactoring—**do not assume active use** unless confirmed by other files.
- **Error Handling Asymmetry**: `GetExcitationVoltageMagnitudeFromEnum` throws on error, while `GetExcitationVoltageEnumFromMagnitude` silently returns `Undefined`. This inconsistency may lead to unhandled exceptions if callers assume symmetric behavior.
- **No Validation on Magnitude Input**: `GetExcitationVoltageEnumFromMagnitude` does not validate input range (e.g., negative voltages), potentially returning `Undefined` for invalid values without clear indication of *why*.
- **Hardcoded Enum Values**: The `SensUnits` enum uses explicit integer values (`0`, `1`, `2`, …). Changing or inserting values may break serialization or persistence if values are stored externally (e.g., in config files or databases).

> **None identified from source alone** for `SensUnits` behavior, but the excitation voltage handling is partially obscured by commented-out code and missing definitions.