HSW Float-Type Water Level Sensor

I. Overview

The HSW float-type water level sensor is a digital sensor that integrates optical, mechanical, and electronic technologies. Through photoelectric conversion, it transforms the angular displacement of the output shaft into corresponding digital values, enabling high-precision measurement of the liquid level height and accurate position confirmation. It features a power-off memory function.

Its working principle is as follows: The water level sensor's measuring wheel is mounted on the encoder's input shaft. One end of the steel wire rope is connected to the float, and the other end is connected to a counterweight. The steel wire rope is wound around the measuring wheel. When the liquid level changes, the float rises or falls with the liquid level, causing the steel wire rope to drive the measuring wheel to rotate. The encoder then outputs the corresponding real-time water level value.

This sensor has a rational structure, strong anti-interference capability, high resolution, large measuring range, long service life, and a signal tracking memory function after power loss. It can be used for long-term liquid level measurement while ensuring stable and reliable performance.

It is widely applicable for measuring the water level of surface water or groundwater in rivers, lakes, reservoirs, ship locks, hydropower stations, hydrological stations, water treatment plants, as well as in petrochemical industries.

III. Working Principle

Instrument structure and working principle:

This instrument consists of a float, steel wire rope, counterweight, measuring wheel, sensor, bracket, output socket, and other components.

The working principle is as follows: The instrument uses the float to sense changes in water level. During operation, the float and counterweight are securely connected to the steel wire rope, which is suspended in the "V"-shaped groove of the water level wheel. The counterweight serves to tighten the steel wire rope and maintain balance. Adjusting the float's counterweight allows the float to operate at the normal draft line. When the water level is constant, the forces on both sides of the float and counterweight are balanced. When the water level rises, the float generates upward buoyancy, causing the counterweight to pull the steel wire rope and drive the water level wheel to rotate clockwise, increasing the reading on the water level sensor's display. When the water level falls, the float sinks, pulling the steel wire rope and driving the water level wheel to rotate counterclockwise, decreasing the reading on the water level sensor's display.

The circumference of the water level wheel in this series of water level sensors is 32 cm, and the water level wheel is coaxially connected to the sensor. For every full rotation of the water level wheel, the sensor also completes one rotation, outputting 1024 sets of corresponding digital codes. As the water level rises or falls, the sensor's shaft rotates by a certain angle, and the sensor synchronously outputs a set of corresponding digital codes (binary cyclic code, also known as Gray code). Instruments with different measuring ranges can output 65,535 sets of different codes, enabling measurement of water level variations from 10 to 20 meters.

The encoded signals can be transmitted via a multi-core cable connected to the instrument's socket to an electronic display or computer in the observation room for monitoring, recording, or data processing. Water level instruments equipped with an RS485 digital communication interface can be directly connected to communication devices or computers, forming part of a hydrological automatic monitoring and reporting system or a remote water monitoring system.

The instrument's built-in RS485 digital communication interface (optional) features addressing and gating functions, enabling long-distance information transmission via a two-wire system. A single pair of twisted signal wires can drive or receive multiple water level (or gate position) sensors, facilitating remote monitoring networking.