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 liquid surface. The buoyant body is equipped with a magnet. When 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.

Analog temperature measurement is carried out using highly accurate temperature sensors of the PT100 or PT1000 type. These sensors utilize the principle of changing the electrical resistance of a metal depending on the temperature. A PT100 sensor consists of a platinum resistance that changes its resistance value as the temperature increases. Similarly, a PT1000 sensor works, but the resistance in ohms is 1000 times larger than that of the PT100. PT sensors are capable of providing very precise and accurate resistance values directly related to the temperature of the liquid or medium in contact. These analog resistance values are then converted and displayed as temperature values via a corresponding measuring instrument or evaluation circuit. The temperature values can also be passed to control and regulation systems to monitor the temperature in the plant and to control or adjust the process if necessary.