The **M2AC-A74-R** is a specific part number belonging to the **M2AC series** of industrial multi-beam safety light curtains/grids, typically manufactured by companies like **Banner Engineering** or **Reer**. These devices are used for perimeter guarding and access control in automated environments. --- ### 1. Technical Specifications The M2AC-A74-R is an **Active/Passive** system component. Specifically, the "-R" suffix usually denotes the **Receiver** unit or the **Remote/Reflector** unit depending on the specific sub-series configuration. | Feature | Specification Details | | :--- | :--- | | **Type** | Multi-beam Safety Light Grid | | **Safety Level** | Type 4 (according to IEC 61496-1) | | **Number of Beams** | 4 Beams | | **Beam Spacing** | 300 mm (Standard for torso/body detection) | | **Operating Range** | Typically 0.5m to 7m (Long range versions available) | | **Supply Voltage** | 24 VDC ± 20% | | **Output Type** | 2 PNP Safety Outputs (OSSD) | --- ### 2. Key Electronic Components & Functions The internal electronics of the M2AC-A74-R are designed for high reliability and fail-safe operation: * **OSSD (Output Signal Switching Devices):** The unit features two independent PNP outputs. These are monitored for short circuits and cross-talk to ensure that a component failure results in a "Stop" command. * **Microcontroller Architecture:** Dual-channel diverse redundancy. Two separate microprocessors compare signals; if they disagree, the system enters a lockout safety state. * **Infrared Emitters/Sensors:** High-power IR LEDs and phototransistors tuned to a specific frequency to prevent interference from ambient light or welding flashes. * **Status Indicators:** Integrated LED diagnostics (usually Red/Green/Yellow) to indicate beam alignment, OSSD status, and internal faults. --- ### 3. Connection Pinout (Typical M12 Connector) Most M2AC models utilize an 8-pin or 5-pin M12 industrial connector. | Pin Number | Function | Wire Color (Typical) | | :--- | :--- | :--- | | 1 | +24V DC | Brown | | 2 | OSSD 1 | White | | 3 | 0V (GND) | Blue | | 4 | OSSD 2 | Black | | 5 | Restart / Reset | Gray | --- ### 4. Implementation Logic The M2AC-A74-R operates on a "Light-On" logic. 1. **Alignment:** The infrared beams from the emitter must hit the receiver. 2. **Safety Loop:** As long as all 4 beams are clear, the OSSD outputs stay HIGH (+24V). 3. **Interruption:** If any beam is broken, the OSSD outputs go LOW (0V) within milliseconds (Response time is typically <25ms), triggering an Emergency Stop in the PLC or Safety Relay.