The **REBS-4-R** is an addressable, 4-relay output module typically used in fire alarm systems and building automation to provide dry contact interfaces for external equipment. --- ### 1. Key Technical Specifications | Feature | Description | | :--- | :--- | | **Model** | REBS-4-R | | **Relay Type** | 4 Form-C (SPDT) Relays | | **Contact Rating** | 2A @ 30VDC / 0.5A @ 125VAC | | **Communication** | Addressable SLC Loop | | **Addressing** | Rotary switches or digital programmer (depending on manufacturer) | | **Operating Voltage** | 15 - 32 VDC (from SLC loop) | | **Status Indicators** | LED (blinks on poll, steady on activation) | --- ### 2. Functional Electronic Components The device acts as a bridge between the low-power logic of a Fire Alarm Control Panel (FACP) and high-current external systems. * **Microprocessor Control:** Manages digital communication with the main control panel. It decodes the unique address assigned to the module and monitors the status of the SLC (Signaling Line Circuit). * **Opto-Isolators:** These electronic components provide electrical isolation between the sensitive control logic and the relay switching circuits to prevent damage from external surges. * **Form-C Relays:** The core physical switching component. Each of the 4 relays provides: * **Common (C)** * **Normally Open (NO)** * **Normally Closed (NC)** * **Addressing Circuitry:** Usually features two rotary dials to set the "Tens" and "Units" for the device address, allowing the panel to command specific relays independently. --- ### 3. Application Use Cases The REBS-4-R is primarily used to trigger secondary systems when an alarm condition is met: 1. **Elevator Recall:** Closing contacts to return elevators to the ground floor. 2. **HVAC Shutdown:** Stopping fans to prevent the spread of smoke. 3. **Door Release:** Cutting power to magnetic door holders. 4. **Pressure Fans:** Activating stairwell pressurization systems. --- ### 4. Wiring Diagram (Conceptual) ```text [ SLC Loop IN ] ----(+)---- [ REBS-4-R ] ----(+)---- [ SLC Loop OUT ] ----(-)---- [ Internal ] ----(-)---- | Logic | / \ [ Relay 1 ] [ Relay 2 ] [ Relay 3 ] [ Relay 4 ] NO C NC NO C NC NO C NC NO C NC ```