The **FLM-2E-R** is a specialized electronic component primarily used in fire alarm systems and industrial control panels. It is commonly identified as a **Relay Module** (Form C) within the Bosch Fire Alarm peripheral line. Below is a detailed breakdown of its electronic specifications and functions. --- ### 1. Technical Specifications The FLM-2E-R is an addressable module that connects to a Local Security Network (LSN) and provides a physical relay output for controlling external devices. | Feature | Specification | | :--- | :--- | | **Input Voltage** | 15 V DC to 33 V DC (via LSN) | | **Current Consumption** | Max 1.0 mA (standby/active) | | **Relay Contact Rating** | 1 A at 30 V DC / 0.5 A at 42.4 V AC | | **Relay Type** | Form C (Change-over contact) | | **Address Range** | 0 to 254 (Set via rotary switches) | | **Protection Class** | IP 30 | --- ### 2. Key Electronic Components The internal circuitry of the FLM-2E-R consists of several critical stages: * **LSN Bus Transceiver:** This sub-circuit handles the data communication between the fire panel and the module. It interprets digital signals to trigger the relay. * **Microcontroller:** A low-power IC that manages the module's unique address and executes logic commands (e.g., "Switch Relay On"). * **Bistable Relay:** The "heart" of the device. It uses an electromagnetic coil to switch between the **Common (C)**, **Normally Open (NO)**, and **Normally Closed (NC)** contacts. * **Rotary Switches:** Three physical dials on the board used to set the decimal address of the module on the loop. * **LED Indicator:** A surface-mount LED that flashes to indicate communication or a steady red light to indicate an active relay state. --- ### 3. Wiring Diagram (Terminal Overview) The module features screw terminals for easy integration. The following table describes the standard pinout: | Terminal | Label | Description | | :--- | :--- | :--- | | **1 & 2** | LSN a1/b1 | Incoming LSN bus connection | | **3 & 4** | LSN a2/b2 | Outgoing LSN bus (to next device) | | **5** | NC | Normally Closed contact | | **6** | C | Common contact | | **7** | NO | Normally Open contact | --- ### 4. Operational Logic The FLM-2E-R operates as a **dry contact**. This means it does not provide voltage to the external device; it simply acts as a switch. 1. **Input:** Receives a digital signal from the Fire Alarm Control Panel (FACP) via the LSN bus. 2. **Processing:** The onboard IC verifies the address. 3. **Output:** The relay coil is energized, moving the contact from NC to NO. This is typically used to shut down HVAC fans, release door magnets, or trigger elevators.