The **F2TS-N3-R** is a specific model within a series of **Thermal Flow Sensors** (often associated with brands like Azbil or similar industrial automation manufacturers). These devices are designed to monitor the flow of liquids or gases by measuring heat dissipation. ### 1. Core Specifications & Technical Overview The "F2TS-N3-R" designation usually breaks down into specific electrical and physical characteristics: | Parameter | Typical Specification | | :--- | :--- | | **Sensor Type** | Thermal Dispersion / Calorimetric | | **Output Type** | NPN Open Collector (indicated by "N") | | **Supply Voltage** | 12 to 24 VDC | | **Response Time** | Fast (often < 1 second) | | **Control Logic** | NO (Normally Open) or NC (Normally Closed) selectable | | **Current Consumption** | Max 30-50 mA | --- ### 2. Internal Electronic Components The device operates using solid-state electronics to translate physical flow into an electrical signal. #### A. The Sensing Element (Thermistor/RTD) The "business end" of the sensor contains two temperature-sensitive resistors: * **Reference Sensor:** Measures the ambient temperature of the fluid. * **Heated Sensor:** Heated to a specific temperature above the fluid. * **Mechanism:** As fluid flows, it carries heat away from the heated sensor. The electronics measure the power required to maintain the temperature difference, which is proportional to the flow velocity. #### B. The Signal Processing Circuit * **Bridge Circuit:** Usually a Wheatstone bridge configuration to detect minute changes in resistance. * **Comparator/Amplifier:** An operational amplifier (Op-Amp) compares the voltage drop across the sensors to a user-defined threshold (set via the potentiometer). #### C. Output Stage (NPN Transistor) The **"N"** in the part number indicates an **NPN Open Collector** output. * When the flow reaches the set point, the internal transistor switches, connecting the output wire to the negative (0V) rail. * This is ideal for interfacing with PLCs (Programmable Logic Controllers) or digital counters. --- ### 3. Connection Diagram & Wiring The F2TS series typically uses a standard 3-wire or 4-wire color code: | Wire Color | Function | Description | | :--- | :--- | :--- | | **Brown** | +V | Power Supply (12-24V DC) | | **Blue** | 0V | Ground / Common | | **Black** | Output | NPN Switch Signal | | **Pink** | Control | (If present) Selects NO/NC mode | --- ### 4. Key Electronic Features * **Potentiometer Adjustment:** An onboard multi-turn trimmer allows the user to set the "Switch Point" electronically. * **LED Indicators:** Usually features a Red/Green LED system to show power status and whether the flow is above or below the threshold. * **Short-Circuit Protection:** Most modern versions include internal protection to prevent the NPN transistor from burning out if the output is miswired. ---