Dark switching, also known as normally closed (NC), is a sensor output mode. According to the provided reference, it activates the output when the receiver doesn't detect light from the emitter. In simpler terms, the sensor is "on" when it's dark.
Here's a breakdown:
- Definition: A sensor output mode where the output is active when no light is detected.
- Alternate Name: Normally Closed (NC). This describes the default state of the switch.
- Mechanism: The sensor constantly monitors for light. If the light source is blocked or fails, the sensor triggers its output.
Dark Switching in Practice
Think of a simple light sensor connected to an alarm. With dark switching:
- Normal State (Light Present): The sensor doesn't trigger the alarm.
- Triggered State (No Light): If someone blocks the light beam, or the light fails, the sensor activates the alarm.
Key Characteristics of Dark Switching (Normally Closed)
| Feature | Description |
|---|---|
| Output State | Active (ON) when no light is detected. |
| Alias | Normally Closed (NC) |
| Use Case | Security systems, object detection where interruption of light is significant. |
Advantages of Dark Switching
- Fail-Safe Operation: If the light source fails, the sensor will trigger its output. This is crucial in many safety applications.
- Easy to Implement: The logic is straightforward - no light, therefore action.
