### Technical Overview: E3F2-R4C4-M The **E3F2-R4C4-M** is a high-performance cylindrical photoelectric sensor manufactured by Omron. It belongs to the E3F2 series, designed for industrial automation tasks such as object detection and positioning. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Sensing Method** | Retro-reflective (Requires a Reflector) | | **Housing Material** | Metal (Brass-Nickel plated) | | **Shape** | M18 Cylindrical (Threaded) | | **Sensing Distance** | 0.1 to 4 Meters (with E39-R1 reflector) | | **Output Type** | NPN Open Collector | | **Operating Mode** | Light-ON / Dark-ON (Selectable via wiring) | | **Supply Voltage** | 10 to 30 VDC | | **Response Time** | 2.5 ms Max. | | **Connection** | M12 4-pin Connector | --- ### 2. Internal Electronic Design The sensor functions through several integrated stages: 1. **Emitter (Infrared LED):** Projects a beam of light toward a target reflector. 2. **Receiver (Photodiode/Phototransistor):** Detects the light reflected back. If an object breaks the beam, the receiver signals the logic circuit. 3. **Amplifier & Comparator:** Processes the weak signal from the photodiode, comparing it against a threshold to determine if the "beam is broken." 4. **NPN Output Stage:** Acts as a switch to "sink" current to the negative rail (0V). This is ideal for connecting to PLC inputs or small relays. --- ### 3. Wiring and Pinout (M12 Connector) Since this model ends in **"-M"**, it utilizes a standard M12 circular connector rather than a fixed cable. | Pin Number | Wire Color (Standard) | Function | | :--- | :--- | :--- | | 1 | Brown | +VCC (10-30V DC) | | 2 | White | Control Input (L-ON/D-ON Select) | | 3 | Blue | 0V (GND) | | 4 | Black | Output (NPN) | --- ### 4. Application Considerations * **Retro-reflective Principle:** Because it requires a reflector, it is excellent for detecting opaque objects. However, very shiny/mirrored objects may sometimes reflect the beam back and fool the sensor unless a polarized version is used. * **Metal Housing:** The "M" in the housing code signifies metal, providing superior durability in environments where physical impact or vibration is likely. * **Ingress Protection:** Usually rated at **IP67**, making it resistant to water and dust in harsh factory conditions.