The working principle of the water leakage alarm is that when water or other conductive liquid leaks, the liquid touches the sensor (leakage sensing cable) to cause a change in the loop resistance, and the special leak detection controller converts the resistance change into a current voltage value, thereby driving the alarm circuit and the relay circuit to activate the alarm.

What the system essentially detects is the different loop impedances input from each loop.

Water leakage alarms are divided into non-locating and locating series, and their working principles are different.

The working principle of the non-locating water leakage alarm is: the leak detection controller equipment is equipped with a set of sensor cable interfaces, which are used to connect the non-locating water leakage sensing cable. When the sensing cable encounters water and conducts and reaches the water leakage threshold, a loop is formed to return data to the device, causing the device to issue a warning; under normal circumstances, the device power supply indicator is always on; when the device detects a water leak, the water leakage warning light will light up , the buzzer inside the device will emit a water leakage warning sound.

The working principle of the locating water leakage alarm is: the locating water leakage sensing cable is composed of 4 different types of wire groups. When a water leakage occurs, the locating sensing cable is connected to the water, reaching the leakage threshold, forming a loop, and returning data to the controller, the water leakage indicator light is on, and the water leakage location is calculated by dividing the water leakage resistance value by the cable impedance of 12.796Ω per meter, with an accuracy of 0.1m.