The **F2TS-NF-R/K** refers to a high-performance **Thermal Flow Switch** (or Flow Sensor) typically manufactured by companies like **Wenglor**. These devices are used to monitor the flow velocity of liquid media in industrial piping systems. Below is a breakdown of its electronic components, specifications, and functional principles. --- ### 1. Technical Specifications The electronics are housed in a rugged casing designed to withstand industrial environments. | Feature | Specification Details | | :--- | :--- | | **Operating Voltage** | 24 V DC (typically 19.2 to 28.8 V DC) | | **Current Consumption** | < 60 mA | | **Switching Output** | PNP (Normally Open/Closed configurable) | | **Switching Current** | Up to 200 mA | | **Response Time** | 1 to 10 seconds (depending on flow change) | | **Temperature Range** | -20°C to 80°C (Medium temperature) | | **Pressure Resistance** | Up to 100 bar | --- ### 2. Electronic Operating Principle: Calorimetric The F2TS-NF-R/K operates on the **calorimetric (thermal) principle**. It contains no moving mechanical parts, which significantly increases its lifespan. * **The Sensor Head:** Contains two thermistors (temperature-dependent resistors). * **The Process:** One thermistor is heated internally to a few degrees above the medium temperature. The second thermistor measures the actual temperature of the medium as a reference. * **Heat Dissipation:** As the liquid flows past the heated sensor tip, it carries heat away. The higher the flow velocity, the greater the cooling effect. * **Signal Processing:** The internal electronics measure the power required to maintain the temperature difference or the temperature drop itself. This is converted into a switching signal. --- ### 3. Key Electronic Components The internal circuitry is composed of several critical stages: 1. **Bridge Circuit:** A Wheatstone bridge configuration is used to compare the resistance values of the two thermistors with high precision. 2. **Comparator/Microcontroller:** Evaluates the voltage differential. This stage determines if the flow rate has crossed the user-defined "Switching Threshold." 3. **Potentiometer (Adjuster):** Usually located under a protective cap, it allows the user to manually set the flow limit at which the electronic output triggers. 4. **LED Display:** Integrated electronics drive a multi-LED display (usually a chain of green/red lights) to indicate the current flow strength relative to the setpoint. 5. **Output Driver:** A transistor-based output (PNP) that interfaces with PLC (Programmable Logic Controller) inputs. --- ### 4. Wiring Diagram Representation The device typically uses a standard M12 connector. ```text Pin 1: L+ (24V DC - Brown) Pin 2: NC (Not connected or Configurable) Pin 3: L- (0V - Blue) Pin 4: Switching Output (PNP - Black) ``` --- ### 5. Application Benefits * **Wear-Free:** Because there are no bearings or rotors, the electronics are not subject to mechanical fatigue. * **Low Pressure Drop:** The sensor probe barely obstructs the pipe. * **Integrated Monitoring:** It monitors both the flow presence and the integrity of the sensor electronics (fail-safe).