The **FMS-2-R/K** is a high-precision digital differential pressure transmitter and controller typically used in laboratory environments, cleanrooms, and hospital isolation rooms. It is designed to monitor and control room pressure, air velocity, or volumetric flow. Below is a breakdown of its electronic components and technical specifications. --- ### 1. Core Electronic Components | Component | Description | | :--- | :--- | | **Microprocessor** | A high-speed digital processor that converts analog sensor data into digital readouts and executes PID control logic. | | **Pressure Transducer** | A ceramic or silicon-based capacitive sensing element that measures minute differences in air pressure. | | **LCD/LED Display** | A backlit digital interface that shows real-time pressure, status alarms, and configuration menus. | | **Signal Converter** | High-resolution A/D (Analog-to-Digital) converters ensure precision down to fractions of a Pascal. | | **Audible Alarm** | An integrated piezo-electric buzzer that triggers during setpoint deviations. | --- ### 2. Input/Output (I/O) Interfaces The FMS-2-R/K acts as a hub between the room environment and the Building Management System (BMS). * **Analog Outputs:** Typically provides **0-10V DC** or **4-20mA** signals to control VFDs (Variable Frequency Drives) or actuators. * **Digital Inputs:** Allows for remote resets or switching between "Occupied" and "Unoccupied" modes. * **Relay Contacts:** Floating (dry) contacts used to trigger external visual strobes or remote alarm monitoring systems. * **Communication Ports:** Usually equipped with **RS-485** or **BACnet MS/TP** protocols for seamless integration into smart building networks. --- ### 3. Technical Specifications | Parameter | Specification | | :--- | :--- | | **Power Supply** | 24 VAC/VDC (±15%) | | **Pressure Range** | Typically -0.5 to +0.5 in. w.c. (adjustable) | | **Accuracy** | ±0.25% to ±0.5% of Full Scale | | **Output Signal** | Selectable 0-5V, 0-10V, or 4-20mA | | **Operating Temp** | 32°F to 120°F (0°C to 50°C) | --- ### 4. Installation and Wiring (Electronic Layout) When wiring the FMS-2-R/K, it is essential to follow the terminal block designations to avoid damaging the CMOS components: 1. **Power Terminals:** Connect to a Class 2 transformer (24V). 2. **Signal Terminals:** Connect the (+) and (-) leads to the BMS controller or the VAV box actuator. 3. **Pressure Ports:** Though mechanical, these connect to the internal electronic transducer via flexible tubing (High and Low ports). ---