The **PRU-22-R** typically refers to a high-performance **Photoelectric Retro-reflective Sensor**, often manufactured by companies like Datasensor (Datalogic) or similar industrial automation brands. It is designed for detecting objects by emitting light and receiving the reflection from a dedicated reflector. --- ### 1. Core Technical Specifications The electronic architecture of the PRU-22-R is built around precision optical sensing and high-speed switching. | Feature | Specification (Typical) | | :--- | :--- | | **Sensing Type** | Retro-reflective (Polarized) | | **Supply Voltage** | 10 - 30 VDC | | **Output Type** | PNP / NPN (Selectable or complementary) | | **Switching Frequency** | Up to 1 kHz | | **Response Time** | ≤ 500 µs | | **Light Source** | Red LED (Visible) or Infrared | --- ### 2. Key Electronic Components #### A. The Optical Transceiver * **Emitter:** A high-intensity LED (usually red for ease of alignment) that pulses light at a specific frequency to avoid interference from ambient light. * **Receiver:** A photodiode or phototransistor tuned to the specific frequency of the emitter. * **Polarizing Filters:** These electronic-optical components ensure the sensor only detects light reflected by a corner-cube reflector, ignoring shiny objects that might cause "false positives." #### B. Signal Processing Circuitry * **Oscillator:** Controls the pulsing of the Emitter LED. * **Amplifier & Comparator:** The weak electrical signal from the photodiode is amplified. A comparator circuit checks the signal strength against a threshold (set via a potentiometer) to decide if the beam is "broken" or "established." #### C. Output Stage * **Transistor Switch:** Usually utilizes a bipolar junction transistor (BJT) or MOSFET to act as a solid-state switch. * **Protection Circuitry:** Includes reverse polarity protection (to prevent damage if wired incorrectly) and short-circuit protection for the output leads. --- ### 3. Connection Diagram (Standard M12 or Cable) The electronic wiring usually follows industrial standards: | Pin/Wire Color | Function | Description | | :--- | :--- | :--- | | **Brown** | +Vcc | Positive power supply (10-30V) | | **Blue** | 0V / GND | Negative power supply | | **Black** | Output (NO) | Normally Open signal | | **White** | Output (NC) | Normally Closed signal / Teach-in | --- ### 4. Operational Indicators The PRU-22-R features LED indicators on the housing to communicate the electronic status: * **Yellow LED:** Output status (lights up when the object is detected). * **Green LED:** Stability/Power (indicates the sensor is powered and the received signal is strong enough for reliable operation).