The **PM-R24** is a U-shaped (slot) micro photoelectric sensor manufactured by Panasonic (formerly SUNX). It is widely used in industrial automation for sensing the presence of objects, limit detection, and counting. --- ### 1. Key Technical Specifications The following table summarizes the primary electronic characteristics of the PM-R24: | Feature | Specification | | :--- | :--- | | **Sensing Range** | 5 mm (fixed) | | **Supply Voltage** | 5 to 24 V DC ±10% | | **Current Consumption** | 15 mA or less | | **Output Type** | NPN Open-collector transistor | | **Output Operation** | Dual output (Light-ON / Dark-ON) | | **Max Load Current** | 50 mA | | **Response Time** | 20 µs or less (under light received condition) | | **Light Source** | Infrared LED (940 nm) | --- ### 2. Physical Structure and Pinout The "R" in PM-R24 refers to its **R-shape** (Right-angle/Ribbon type) housing, which allows for versatile mounting in tight spaces. #### Terminal Configuration The device typically features four connection points: 1. **V+ (Brown):** Positive power supply (5-24V DC). 2. **L (Pink):** Control input for switching between Light-ON and Dark-ON modes. 3. **Out (Black):** NPN Output signal. 4. **V- (Blue):** Ground (0V). --- ### 3. Internal Circuitry and Operation The sensor operates using an **Emitter** and a **Receiver** facing each other across a 5mm gap. * **The Emitter:** An infrared LED constantly emits light. * **The Receiver:** A phototransistor detects the light. * **Logic:** * When the beam is **uninterrupted**, the phototransistor conducts. * When an object **blocks** the beam, the phototransistor stops conducting, triggering the output state change. --- ### 4. Comparison with Similar Models The PM-24 series comes in different shapes to fit various mechanical requirements: | Model | Shape Description | | :--- | :--- | | **PM-K24** | K-type (Standard U-shape) | | **PM-L24** | L-type (L-shaped housing) | | **PM-F24** | F-type (Front mounting) | | **PM-R24** | R-type (Right-angle/Rear mounting) | --- ### 5. Application Precautions * **Wiring:** Since it is an NPN output, the load should be connected between the Output wire and the Positive supply. * **Environment:** While robust, avoid direct sunlight on the receiver to prevent false triggering. * **Object Size:** The sensor can detect opaque objects as small as 0.8 x 1.8 mm.