The operating principle for this probe is the same as for all Hycontrol vibrating probe level switches. The probe uses a piezoelectric crystal to force a blade to oscillate at its fundamental frequency (also called natural resonance). When the blades come into contact with the process media the natural frequency of oscillation is dampened; the electronics sense the change in frequency which causes the unit to switch.
DP650 is a simple vibrating switch for solids, with four-metre-long cable insertion. It should be mounted from the top of the vessel only.
The DP650 has a single solid stainless steel rod which is vibrated by the piezoelectric element. Thanks to its small size, it is ideal for use in small hoppers containing granular materials or pellets, like plastics, food or grain. Still, the circular construction of the DP650 means that it is not as sensitive to light materials. DP650 probes should only be used on materials which have a bulk density greater than 20 grammes per litre.