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  • Highly robust tuning fork
  • 150 mm tuning forks
  • For process temperatures up to 250 °C
  • For process pressures up to 16 bar (232 psi)
  • High abrasion resistance
  • Insensitive to build-up
  • Set-up without filling
  • Detection of solids in water
  • Detects bulk solids up to >0.008 g/cm³ (0.0003 lbs/in³)
  • Maintenance-free
  • Tuning fork suitable up to density < 20 g/l
  • Product independent switch point
  • Output: Relay, transistor, two-wire output, contactless electronic switch
  • ATEX approvals available


The KROHNE OPTISWITCH 3100 C is a compact vibration level switch. It is designed for industrial use in all areas of process technology but preferably used for bulk solids. Due to the exact reproducibility of the switching point and the integrated function monitoring, the OPTISWITCH can be used as overfill protection, dry-run protection or pump protection. With a simple and robust measuring system, OPTISWITCH 3100 C is virtually unaffected by the chemical and physical properties of the bulk solid. Neither adhesions on the oscillating fork nor container vibrations have an impact on the measurement.

In industrial settings, heavy dust build-up and mechanical stresses are a challenge for any limit switch. This is not a problem for OPTISWITCH: The rugged unit detects the limit in the silo independently of the properties of the bulk goods and reliably warns against overfilling. OPTISWITCH even masters tall, narrow silos due to the product-independent switching point. This is especially beneficial for rapid or recurring changes of bulk goods where the product properties can change from filling to filling. Even very light bulk goods (such as aerosil ®) can be reliably and safely detected using OPTISWITCH.

The KROHNE OPTISWITCH 3100 C is a versatile instrument that can be mounted in nearly any position and used in applications with process temperatures up to 250 °C (482 °F) and pressures of up to 16 bar (232 psi). A number of options are available for customizing the meter to the needs of the user including a version for solid detection in water. Because OPTISWITCH has practically no moving parts, it is not subject to wear.