Level measurement in automated industry 4.0

Automated level measurement of substances in storage containers is indispensable in Industry 4.0. Continuous monitoring of the fill levels is a prerequisite for a safe and stable production process. WayCon position measurement technology offers demand-oriented, automated level measurement for many industries.
A distinction is made between two main fields:

- The monitoring of the filling levels for replenishment or stopping of the filling process as well as the query of the bearing status

- The triggering of safety measures (such as shutdown) when a maximum or minimum filling level is reached

In the first case, one speaks of continuous level control. The level of the substances to be monitored can be recorded at any time, at any position of the container, and ensures a continuous reading. The advantage here is that capacity planning can be adapted to the production process at any time in the event of irregular use.

In the second case, the term "limit level measurement" is used. Predefined maximum and/or minimum fill levels are defined and monitored during the production process. An action is triggered when the corresponding limit values are exceeded or not reached. This monitoring is particularly suitable for continuous processes for the timely supply or removal of the required substances. In addition, the level measurement serves as a safety measure, e.g. to prevent overfilling by shutting down the system.

The different methods of level measurement
The level measurements are made by contacting or non-contacting sensors, which determine the distance between the sensor and the object to be measured.

Level measurement using ultrasound
Classic level measurement is carried out using ultrasonic sensors. Measurement by ultrasonic sensors is a non-contact measurement and is suitable for continuous level control as well as for level limit measurement. Ultrasonic sensors emit a high-frequency vibration which is reflected by the target. Based on the runtime between "send and receive" the distances are determined. The advantage of this measurement method is that it is independent of the substance used, such as oil or water.

Level measurement using magnetostrictive principle
Magnetostrictive sensors operate contactless and wear-free. A short, constant current pulse is sent through a waveguide. A freely movable position magnet reacts to the current pulses with an opposing torsion wave. A changed position of the position magnet causes a changed running time of the response pulse. This is finally converted into an electrical measurement signal with the aid of a pulse converter. The magnet is embedded in a float and ensures permanent detection of the level. Magnetostriction works without contact, but the float must have contact with the medium to be measured.


Level measurement by means of draw wire Draw wire sensors belong to the contacting measurement methods. A stainless steel measuring cable is wound in a single layer onto a cable drum with a pretensioned mainspring. The measuring cable is connected to the measuring object and pulls the measuring cable out of the drum when the position is changed. The axis of the drum is permanently connected to an electronic element that converts the mechanical rotary motion into a proportional electrical signal. For level measurement, the measuring cable is connected to a float which is in contact with the medium to be measured.

Level measurement using capacitive principle
Capacitive sensors measure the change in capacitance. Here, the sensor and the object to be measured each form a plate as in a plate capacitor. The electric field between them is detected and changes according to the distance. This measuring method is non-contact and is suitable for both continuous measurement and level limit measurement.