Water Level Sensor

A water level sensor is a component used in water supply and drainage systems to monitor the level of water in tanks, reservoirs, or pipes. It provides essential data for system operation, helping to prevent overflow or dry running, and enabling automated control. By measuring water level, the sensor contributes to maintaining proper water pressure, managing storage capacity, and triggering alarms or control actions when preset thresholds are reached. The sensor operates by detecting changes in physical properties such as pressure, capacitance, conductivity, or ultrasonic reflection caused by water presence or level changes, and converts these changes into electrical signals that can be interpreted by monitoring or control systems. Typical specifications include a measuring range of 0–5 m (custom ranges available), accuracy of ±0.5% FS (including linearity, hysteresis, and repeatability), a 4–20 mA two-wire loop-powered output signal, and a supply voltage of 12–36 V DC with reverse polarity protection. The operating temperature range is -20 to 85 °C for media temperature (ambient may differ). The process connection is G1/2 thread per DIN 3852, and the ingress protection rating is IP67 per IEC 60529, suitable for submerged applications. Wetted parts are made of stainless steel 316L per ASTM A276 (optional Hastelloy). Response time is ≤500 ms to reach 90% of final value, and the overpressure limit is 2× full scale without damage. Weight ranges from 0.3 to 0.5 kg depending on cable length and options. Materials include stainless steel, plastic housing, and electronic components. This directory entry provides reference values; actual model-specific values and standards must be verified with the legal manufacturer or supplier.

The sensor detects water level by measuring changes in physical properties caused by water presence or level variation. Common methods include pressure sensing, where hydrostatic pressure increases with depth; capacitance sensing, where water alters the dielectric between electrodes; conductivity sensing, where water completes an electrical circuit; or ultrasonic reflection, where sound waves reflect off the water surface. These changes are converted into an electrical signal, typically a 4–20 mA loop, which is transmitted to a monitoring or control system. The signal can be used to display level, trigger alarms, or activate pumps and valves. The sensor's accuracy and response time depend on the sensing principle and environmental conditions. Proper installation and calibration are necessary to ensure reliable operation.