Why complicated when things can be simple? Cable probes: A tried and tested technology

A range of possibilities and a variety of sensors exist for filling level measurement. The popular hydrostatic method of filling level measurement is and remains a classic, particularly as intelligent cable probes from ipf are ideally suited to this type of measurement.


The cable probes measure filling levels by determining hydrostatic pressure. The physical principle describes the effect of the weight force of an undisturbed (i.e. flow-free) liquid on a measurement point. Here, the difference between the pressures at the liquid surface and at the container bottom that is produced as a result of the height of the liquid column is measured. The measured difference in pressure is therefore a direct measure of the filling level and the height of the li-quid over the sensor.

Owing to their high precision in practical use, cable probes are ideal for liquid media such as water, wastewater, solvents, sludge, fat and much more. Moreover, the sensors present a number of advantages. Only one sensor is required for filling level control. Only the device appropriate for the container height and with the corresponding pressure range is needed for the specific application. No other settings are necessary for these easy-to-install sensors. Furthermore, cable probes are completely maintenance-free and enable extremely precise and continuous filling level measurement that is not influenced by environmental conditions, such as electrical fields.


Cable probes consist of a sensor and an evaluation unit which are connected to a carrier cable for voltage supply and signal transmission. The sensor is lowered into a container using the carrier cable. So-called cable anchor clamps are used to secure the "hanging" sensor. Alternatively, the sensor can also be screwed from outside into a side wall of the container. ipf electronic currently offers three sensors for hydrostatic filling level measurement, whereby the FY98C300 (degree of protection IP68) is precisely calibrated to a water column of 1.50m. The FY98C711 and FY98E214 (both IP68), however, are designed for pressure ranges from 0 to 0.2bar and 0 to 0.4bar respectively. All three cable probes are suitable for use in media with temperatures ranging from -20°C to +70°C.