Based on the model number **FTS-70-R**, this typically refers to a **Thermal Flow Switch** or **Calorimetric Flow Sensor**, commonly manufactured by companies like *Negele Messtechnik (Anderson-Negele)*. This electronic component is designed to monitor the flow rate of liquids in pipes, often used in food, beverage, and pharmaceutical industries due to its hygienic design. --- ### 1. Core Operating Principle The FTS-70-R operates on the **calorimetric (thermal) principle**. * **Heating Element:** An internal probe is heated slightly above the temperature of the medium. * **Measurement:** As the liquid flows past the probe, it carries heat away. * **Calculation:** The electronics measure the power required to maintain the temperature difference. Higher flow equals faster cooling, which the internal circuit converts into a flow velocity signal. ### 2. Electronic Specifications Below are the typical electronic characteristics for the FTS-70-R series: | Feature | Specification | | :--- | :--- | | **Operating Voltage** | 18...36 V DC | | **Current Consumption** | < 100 mA | | **Output Signal** | PNP (Switching) or 4...20 mA (Analog) | | **Switching Logic** | Active high (R-type configuration) | | **Response Time** | 2 to 10 seconds (Adjustable) | | **Electrical Connection** | M12 Plug-in connector (typically 4-pin) | ### 3. Key Electronic Components The internal architecture of the device consists of: 1. **RTD Sensors:** Usually two Pt1000 platinum resistors—one for reference temperature and one for heating/sensing. 2. **Microprocessor:** Processes the temperature differential and compensates for fluctuations in the medium's ambient temperature. 3. **Potentiometer/Interface:** Often includes a small screw-adjustment or digital interface to set the "Switch Point" (the specific flow rate where the output triggers). 4. **LED Indicators:** Visual feedback (Green for "Flow", Red for "No Flow") integrated into the housing. --- ### 4. Wiring Diagram (Typical) The wiring for an M12 4-pin connector on this device usually follows this logic: ```text Pin 1: +24V DC (Brown) Pin 2: Not used or Analog Output (White) Pin 3: 0V / GND (Blue) Pin 4: PNP Switch Output (Black) ``` --- ### 5. Application Benefits * **No Moving Parts:** Unlike mechanical paddles, the electronic thermal sensor does not wear out or clog. * **Temperature Independent:** The electronic compensation allows it to function accurately even if the liquid temperature changes. * **Hygienic Electronics:** The circuitry is fully potted and sealed in stainless steel (typically 316L) to withstand CIP (Clean-in-Place) processes.