The **E3B2-R7M4D-US** is a heavy-duty, multi-voltage photoelectric sensor manufactured by Omron. It is designed for industrial sensing applications, specifically utilizing the **retro-reflective** sensing method. ### 1. Technical Specifications The following table outlines the core electronic and physical characteristics of the device: | Feature | Specification | | :--- | :--- | | **Sensing Method** | Retro-reflective (requires a reflector) | | **Sensing Distance** | 7 meters (approx. 23 feet) | | **Supply Voltage** | 24 to 240 VAC / 12 to 240 VDC (Universal) | | **Output Type** | Relay Output (SPDT - Single Pole Double Throw) | | **Control Output** | 3A at 250 VAC (Resistive Load) | | **Response Time** | 30 ms Max. | | **Light Source** | Infrared LED | | **Operating Mode** | Light-ON / Dark-ON (Selectable via switch) | --- ### 2. Key Electronic Components & Functions #### A. Universal Power Supply One of the standout features of the E3B2 series is its integrated switching power supply. It can accept a wide range of voltages (both AC and DC), making it highly versatile for different global power standards without needing additional transformers. #### B. Relay Output (Dry Contact) Unlike solid-state NPN/PNP sensors, this model uses a mechanical **relay output**. * **Advantage:** It can switch high-current loads (up to 3A) directly. * **Isolation:** The output circuit is electrically isolated from the sensor's power supply circuit. #### C. Built-in Timer Functions The "D" in the suffix often denotes the inclusion of a logic/timer module. This allows for: * **ON-delay:** Delays the trigger after an object is detected. * **OFF-delay:** Keeps the signal active for a set time after the object leaves. * **One-shot:** Provides a pulse of a specific duration regardless of how long the object stays in front of the sensor. #### D. Infrared Detection Logic The sensor emits an infrared beam. In a retro-reflective setup, the beam bounces off a reflector and returns to the sensor's receiver. If an object breaks this beam, the internal logic triggers the relay. --- ### 3. Connection Diagram (General) The wiring is typically handled via a terminal block inside the housing: ```text Terminal 1 & 2: Power Input (24-240V AC/DC) Terminal 3: Relay Common (COM) Terminal 4: Relay Normally Closed (NC) Terminal 5: Relay Normally Open (NO) ``` --- ### 4. Applications * **Conveyor Systems:** Detecting large boxes or pallets. * **Gate Automation:** Detecting vehicles or pedestrians. * **Material Handling:** Counting items in rugged environments where high voltage is preferred over 24V DC logic.