The **FTS-0B-R/K** is a specific series within the **FTS** range of thermal flow sensors, typically manufactured by companies like **ifm electronic**. These sensors are designed to monitor the flow velocity and temperature of liquid media (such as water, oils, or coolants) in industrial piping systems. Below is a breakdown of the electronic components, specifications, and operational logic. --- ### 1. Technical Specifications The "R/K" designation often refers to specific output configurations (Relay or Control) and connection types. | Feature | Specification (Typical) | | :--- | :--- | | **Operating Voltage** | 18...30 V DC | | **Current Consumption** | < 60 mA | | **Output Type** | PNP/NPN (Switching) or Analog (4-20 mA) | | **Media Temperature** | -25°C to 80°C | | **Pressure Rating** | Up to 100 bar | | **Protection Rating** | IP 67 (Dust tight/Water immersion) | | **Connection** | M12 Connector or hard-wired cable | --- ### 2. Electronic Operating Principle The FTS series utilizes the **Calorimetric (Thermal) Measuring Principle**. This involves no moving parts, making it highly reliable. * **The Sensing Element:** The probe contains two high-precision thermistors (RTDs). * **The Heating Process:** One thermistor is heated internally to a few degrees above the medium temperature. The other thermistor measures the actual ambient temperature of the fluid. * **Heat Dissipation:** As fluid flows past the probe, it carries heat away from the heated sensor. * **The Calculation:** The electronics measure the power required to maintain the temperature difference. Higher flow rates cause faster cooling, requiring more power. The internal microprocessor converts this power delta into a flow velocity signal. --- ### 3. Key Electronic Components The internal PCB (Printed Circuit Board) of the FTS-0B-R/K consists of the following: 1. **Microcontroller (MCU):** Processes the raw analog resistance changes from the thermistors and linearizes the data. 2. **Signal Converter:** Translates the MCU data into standard industrial signals (IO-Link, 4-20mA, or frequency). 3. **IO-Link Interface:** Modern versions include an IO-Link chip for digital communication, allowing for remote parameter setting and diagnostics. 4. **LED Display/Indication:** Usually features a multi-color LED chain to provide a visual "at-a-glance" status of the flow rate and switching points. --- ### 4. Wiring and Output Logic Depending on the "R/K" suffix, the wiring usually follows this standard M12 pinout: * **Pin 1 (Brown):** L+ (18-30V DC) * **Pin 2 (White):** Out 2 (Analog signal or Temperature switch) * **Pin 3 (Blue):** L- (0V / Ground) * **Pin 4 (Black):** Out 1 (Flow switching signal / IO-Link) ---