The **E3JM-R4M4T** is a high-performance photoelectric sensor manufactured by Omron. It is a **retro-reflective** type sensor that includes a built-in timer function and operates on a universal voltage range. --- ### 1. Key Technical Specifications The following table summarizes the primary electronic and physical characteristics: | Feature | Specification | | :--- | :--- | | **Sensing Method** | Retro-reflective (requires a reflector) | | **Sensing Distance** | Up to 4 meters (using E39-R1 reflector) | | **Supply Voltage** | 12 to 240 VDC or 24 to 240 VAC (50/60 Hz) | | **Output Type** | Relay Output (SPDT) | | **Contact Capacity** | 3A at 250 VAC / 3A at 30 VDC | | **Timer Function** | ON-delay / OFF-delay / One-shot (adjustable 0.1 to 5s) | | **Light Source** | Infrared LED | | **Connection** | Terminal block (PG13.5 cable gland) | --- ### 2. Internal Electronic Components & Logic The sensor consists of four main electronic stages: #### A. Power Supply Stage The sensor features a **Universal Voltage Power Supply**. Internally, it uses a bridge rectifier and a voltage regulator to convert incoming AC or DC power (up to 240V) into the low-voltage DC required for the internal circuitry. #### B. Emitter and Receiver Stage * **Emitter:** Uses an **Infrared LED** to pulse a beam of light. * **Receiver:** Uses a **Photodiode** paired with a frequency filter. The filter ensures the sensor only reacts to the specific pulse frequency of its own emitter, preventing interference from ambient sunlight or room lighting. #### C. Control and Timing Logic (The "T" Model) The "T" in the model name indicates the **Timer Function**. This is controlled by internal potentiometers (dials) that allow the user to modify the output signal: 1. **ON-Delay:** The output waits for a set time after an object is detected before activating. 2. **OFF-Delay:** The output stays active for a set time after the object has left the sensing field. 3. **One-Shot:** The output triggers for a fixed duration regardless of how long the object stays in front of the sensor. #### D. Output Stage (Relay) Unlike NPN/PNP transistor outputs, the E3JM-R4M4T uses a **Mechanical Relay (SPDT)**. This provides "dry contacts," meaning it acts as a simple switch. * **Advantage:** Can switch high-current loads and different voltages than the supply. * **Disadvantage:** Slower response time (approx. 30ms) compared to solid-state sensors. --- ### 3. Wiring Diagram (Terminal Block) The internal terminals are organized as follows: ```text Terminal 1 & 2: Power Supply (12-240VDC / 24-240VAC) Terminal 3: Relay Common (COM) Terminal 4: Relay Normally Closed (NC) Terminal 5: Relay Normally Open (NO) ``` --- ### 4. Application Considerations * **Polarized Light:** This model does not always include an MSR (Mirror Surface Rejection) function by default. If you are sensing shiny metallic objects, you may need the "R4M4-G" version or ensure the sensor is angled correctly. * **Environmental Protection:** It is rated **IP66**, meaning the electronics are protected against powerful water jets and dust.