The **FLM-H4-R** is an electronic component primarily associated with **Bosch Security Systems**. It is a **Field Longitudinal Module** designed for fire alarm systems, specifically serving as a **4-wire Conventional Zone Monitor**. Below is a detailed breakdown of its electronic specifications and functions. --- ### 1. Technical Specifications The following table highlights the core electrical characteristics of the FLM-H4-R module: | Parameter | Value / Specification | | :--- | :--- | | **Operating Voltage** | 24 VDC (Nominal) | | **Current Consumption** | < 100 mA | | **Input Channels** | 1 (Monitoring 4-wire conventional detectors) | | **Output Type** | Relay Contact (Fail-safe operation) | | **EOL Resistance** | 3.9 kΩ (Standard) | | **Protection Class** | IP 30 | | **Operating Temperature** | -20 °C to +50 °C | --- ### 2. Key Electronic Functions The FLM-H4-R acts as an interface between a fire panel's digital bus and conventional sensing devices. * **Zone Monitoring:** It monitors a single branch of 4-wire conventional detectors for alarms, short circuits, and wire breaks (open circuits). * **Reset Functionality:** It features an integrated electronic power-reset mechanism. This allows the fire panel to briefly interrupt power to the 4-wire detectors to reset them after a triggered alarm. * **Galvanic Isolation:** The module provides electrical isolation between the Local SecurityNetwork (LSN) bus and the conventional zone, protecting the main panel from surges or faults on the field wiring. * **Addressing:** It uses rotary switches or electronic software addressing to identify itself on the LSN loop. --- ### 3. Wiring Configuration The "H4" in the model name signifies its specialization for **4-wire** circuits. In this setup: 1. **Two wires** are used for the 24V power supply to the detectors. 2. **Two wires** are used for the alarm signaling loop. #### Typical Connection Diagram (Simplified) ```text [ FIRE PANEL LSN BUS ] <---> [ FLM-H4-R MODULE ] | +--- [ 24V Power Out ] ---> [ Detector 1 ] ... [ Detector N ] | +--- [ Alarm Input ] <--- [ EOL Resistor ] ``` --- ### 4. Application Use Case This module is typically used when upgrading an older building that already has 4-wire smoke detectors installed, or when using specialized detectors (like beam detectors or flame detectors) that require separate 24V power and a relay contact interface to talk to a modern addressable fire panel.