The operating principle of a float switch based on a reed contact relies on the use of a reed switch as the switching element. A float switch consists of a buoyant body, also known as a float, which floats on the surface of the liquid. The buoyant body is equipped with a magnet. As the liquid level changes, the buoyant body moves accordingly, either upward or downward. When a certain level is reached, the magnet approaches the reed contact. The reed contact consists of two ferromagnetic contact blades placed within a glass capsule. These blades are separated by a small air gap. When the magnet of the buoyant body reaches the reed contact, the magnetic field attracts the ferromagnetic blades, bringing them together. This closes the contact blades, completing the electrical circuit. This closed circuit can be used to send a signal, for example, to trigger an alarm or control a motor.

Temperature measurement is carried out using highly accurate temperature sensors of the PT100 or PT1000 type. These sensors utilize the principle of changes in the electrical resistance of a metal depending on temperature. A PT100 sensor consists of a platinum resistance that changes its resistance value as the temperature increases. Similarly, a PT1000 sensor works the same way, but the resistance in ohms is 1000 times greater than that of a PT100 sensor. The PT sensors can provide very precise and accurate resistance values, which are directly related to the temperature of the liquid or medium in contact with them. These analog resistance values are then converted into temperature readings by an appropriate measuring device or evaluation circuit. The temperature values can also be passed on to control and regulation systems to monitor the temperature in the system and, if necessary, to control and regulate the process.