The **W2PA-1AE-R2/CE** is a high-performance, non-contact safety switch manufactured by **IDEC**. It belongs to the **W2PA series** of RFID-based magnetic safety interlocks, designed to monitor the status of guards, gates, and covers in industrial automation. Below is a detailed breakdown of its electronic components and technical specifications. --- ### 1. Core Technical Specifications The device operates using **RFID (Radio Frequency Identification)** technology, which provides a higher level of tamper protection compared to traditional magnetic switches. | Feature | Specification | | :--- | :--- | | **Operating Voltage** | 24V DC (+10% / -15%) | | **Output Type** | 2 x OSSD (Output Signal Switching Device) | | **Auxiliary Output** | 1 x PNP transistor output (for monitoring) | | **Sensing Distance** | 10 mm (nominal) | | **Response Time** | < 100 ms | | **Protection Rating** | IP67 (dust and water-resistant) | | **Safety Standard** | Category 4, PLe (ISO 13849-1), SIL 3 | --- ### 2. Electronic Components & Working Principle The system consists of two physical parts: the **Sensor (Switch)** and the **Actuator**. #### A. RFID Sensing Module Unlike simple reed switches, this part contains a microchip and an antenna. - **The Actuator:** Contains a passive RFID tag with a unique or standard code. - **The Sensor:** Emits a high-frequency field to power the actuator and read its code. - **Coding Levels:** This specific model usually supports "Standard" or "Unicode" variants to prevent unauthorized bypassing using spare magnets. #### B. OSSD Safety Outputs The "Electronic Parts" responsible for safety are the **dual OSSD outputs**. - These outputs perform self-diagnostics by sending short pulses (test pulses) to detect short circuits to the power supply or between channels. - If a fault is detected, the electronics automatically shut down the safety circuit. #### C. LED Diagnostics The device includes internal circuitry to drive multi-color LED indicators: * **Green:** Guard closed, safety outputs ON. * **Red:** Guard open, safety outputs OFF. * **Yellow/Flashing:** Fault detected or misalignment. --- ### 3. Wiring Diagram (Terminal Overview) The W2PA series typically uses an M12 8-pin connector or a fixed cable. | Wire Color / Pin | Function | Description | | :--- | :--- | :--- | | Brown | +24V DC | Main logic power supply | | Blue | 0V (GND) | Common ground | | Black | OSSD 1 | Safety Output Channel 1 | | White | OSSD 2 | Safety Output Channel 2 | | Red | Reset/EDM | External Device Monitoring | | Pink | Aux Output | Signal to PLC (non-safety) | --- ### 4. Key Advantages of the Electronic Design 1. **Misalignment Tolerance:** Because it is electronic/RFID, it can handle slight physical misalignment better than mechanical keys. 2. **Series Connection:** The electronics allow for "Daisy Chaining." You can connect multiple W2PA units in series while maintaining a **PLe/SIL3** safety rating. 3. **Solid State:** No moving mechanical parts inside the switch, leading to a significantly longer electronic lifespan compared to mechanical limit switches.