The **FLM-D1-R** is an electronic component primarily used in fire alarm systems. Specifically, it is a **Dual Relay Module** within the Bosch family of fire safety devices. It is designed to provide dry contact relay outputs that are controlled by a Fire Alarm Control Panel (FACP) via the Local Security Network (LSN). --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and physical characteristics of the FLM-D1-R: | Specification | Details | | :--- | :--- | | **Product Type** | Dual Relay Module (Addressable) | | **Input Voltage** | 15 V DC to 33 V DC (LSN range) | | **Relay Contact Type** | 2 × Form C (Changeover contacts) | | **Contact Rating (Resistive)** | 2 A @ 30 V DC / 0.5 A @ 125 V AC | | **Current Consumption** | Approx. 1.7 mA (Normal operation) | | **Addressing** | Manual (Rotary switches) or Automatic | | **Operating Temperature** | -20 °C to +50 °C | --- ### 2. Core Electronic Components & Functions The module operates as an interface between the low-power digital signal loop and high-power auxiliary devices. * **LSN Bus Interface:** The module contains integrated circuitry to communicate with the Bosch LSN bus. It receives digital commands to toggle the relays and sends status reports back to the panel. * **Form C Relays:** These are the "mechanical" electronic parts. A Form C relay includes a Common (C), Normally Open (NO), and Normally Closed (NC) contact. This allows the device to either complete or break a circuit when activated. * **Rotary Switches:** Located on the PCB, these hardware switches allow technicians to manually set the module's address (0-254) for identification by the control panel. * **On-board LEDs:** Typically features a status LED (often red or green) that indicates the communication status with the LSN loop or activation state of the relays. --- ### 3. Application Use Cases Because it provides two independent dry contacts, the FLM-D1-R is commonly used to trigger: 1. **Elevator Recall:** Sending a signal to the elevator controller to return to the ground floor during a fire. 2. **HVAC Shutdown:** Turning off air handling units to prevent the spread of smoke. 3. **Door Release:** De-energizing magnetic door holders to close fire doors. 4. **Extinguishing Systems:** Triggering secondary fire suppression or signaling external sirens. --- ### 4. Wiring Diagram Concept While specific wiring depends on the load, the general terminal structure is as follows: ```text [ LSN In + / - ] ----> [ Internal Microprocessor ] ----> [ Relay 1 (C/NO/NC) ] [ LSN Out + / - ] ----> [ Relay 2 (C/NO/NC) ] ``` ---