With the LFT, Sick has developed an innovative filling level measurement system for use with numerous water and oil-based liquids.
Maximum independence regarding installation and environmental conditions is achieved by combining TDR (Time Domain Reflectometry) technology with a highly resistant coaxial measurement probe made of 1.4404 stainless steel.
With measurement lengths of 30 - 1,990mm (almost entirely free of dead zones), g¾a or ¾-inch NPT connection threads and teach-in configuration via just a single button, the LFT filling level measurement system is particularly suitable for small to medium-sized containers and tanks.
The LFT’s innovative measurement process, during which low-energy microwave pulses are gathered in a stainless steel coaxial probe, is what makes it so special.
Some of the electromagnetic pulses are reflected when they hit the surface of the filling medium. The device uses the length of time required for them to reach the sensor head to calculate the current filling level with an accuracy of a few millimetres.
This technology means that filling level detection with the LFT is independent of installation, container and medium properties, because the environment within the measurement probe is always defined and interference-free. There is no need to re-configure the LFT when the physical properties of the liquid change.
Analogue and switching outputs can be used individually
Filling level detection tasks can be solved individually with the LFT. The sensor has one 4 - 20mA analogue output and four switching outputs that can each be separately programmed. Two switching points can be linked with one another if a min-max control is desired, e.g. for controlling a pump between a minimum and a maximum level.
The LFT is easy to operate. A single button is used to set the switching points, toggle the switching outputs between N.O. and N.C. contacts, define the hysteresis for the switching outputs and set the required measurement range along the coaxial probe.
Wide range of applications
Typical areas of use for the LFT are containers and tanks in the water and sewage industry, machine construction, machine tools or CIP (cleaning-in-place) filling plants, where the almost completely friction and maintenance-free device proves its high precision and robustness with the most varied of filling media such as coolants; grinding and hydraulic oils; or detergents, disinfectants and degreasers.