The **KUS-4W1-R** is a specific model of an **Ultrasonic Fuel Level Sensor**, typically manufactured by KUS (formerly known as Wema). It is designed to measure the fuel level in tanks without making physical contact with the liquid, using ultrasonic sound wave technology. --- ### 1. Core Specifications The following table highlights the primary technical parameters of the KUS-4W1-R sensor: | Feature | Specification | | :--- | :--- | | **Technology** | Ultrasonic (Non-contact) | | **Input Voltage** | 10V - 32V DC | | **Output Signal** | 0 - 190 $\Omega$ (Standard European Ohm Range) | | **Resolution** | $\leq$ 2mm | | **Accuracy** | $\pm$ 2% | | **Blind Zone** | $\leq$ 50mm (Area directly under the sensor that cannot be measured) | | **Operating Temp** | -40°C to +85°C | | **Protection Rating** | IP67 (Dust tight and water immersion resistant) | --- ### 2. Internal Electronic Components The device functions through a complex interaction of electronic subsystems: 1. **Ultrasonic Transducer:** The "heart" of the device. It contains a piezoelectric crystal that converts electrical energy into high-frequency sound pulses and converts the returning echoes back into electrical signals. 2. **Signal Processor (MCU):** An internal microcontroller that calculates the time-of-flight (the time it takes for the pulse to hit the fuel surface and return). It uses this time to determine the distance. 3. **Temperature Compensation Circuit:** Since the speed of sound changes with air temperature, the electronics include a thermistor to adjust the calculations for accuracy in varying climates. 4. **Signal Converter:** Translates the digital distance measurement into an analog resistance signal (0-190 ohms) so it can communicate with standard analog fuel gauges. --- ### 3. Wiring Configuration The sensor typically features a 4-wire or specialized connector setup to handle both power and signal transmission: * **Red Wire:** Positive Power Supply (+10-32V). * **Black/Blue Wire:** Ground (Negative). * **Green/Yellow Wire:** Signal Output (to the Gauge). * **Calibration Wire:** Used during installation to set the "Full" and "Empty" points for the specific tank height. --- ### 4. Key Advantages * **No Moving Parts:** Unlike traditional float sensors, there are no mechanical levers to jam or wear out. * **Chemical Resistance:** Because it never touches the fuel, it is highly resistant to corrosive additives or different fuel types (Diesel, Gasoline, Water). * **High Precision:** Offers much higher resolution than standard reed-switch sensors.