KROHNE”s OPTISWITCH 3000 is designed for detecting the level of bulk solids while OPTISWITCH 5000 is designed for liquid level. Both level switches are suited for overfill and dry-run applications in a variety of industries. A tuning fork, the switches” vibrating element, is energized piezoelectrically and vibrates at the mechanical resonance frequency. The piezos, which are fixed mechanically, are not subject to temperature shock limitations. When the tuning fork is immersed in the liquid or solid, the vibrating frequency changes and is detected by the integrated oscillator and converted into a switching command. Both the OPTISWITCH 3000 and 5000 series are available in a standard and extended tube version, and the OPTISWITCH 3000 series is also offered in a cable version.