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Marine high level alarm switch


KONGSBERG / Autronica marine level switches

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Replaces the older Autronica high level alarm sensor GL-7A.

KONGSBERG / Autronica GL-7B Level Switch

The Kongsberg GL-7B uses a capacitive measuring principle for level detection.

The capacitance is measured between the inner and the outer electrode ring. The inner electrode ring is insulated with PTFE, and the outer ring is made of acid resistant steel (AISI 316). If a liquid enters the gap between the two electrode rings, the capacitance will be altered. This change in capacitance is used to detect liquid / no liquid.

The GL-7B Level Switch can be used both in conducting and non-conducting liquids. The switches do not require any re-adjustment due to different types of cargoes (liquids). Both single and dual types are available. Functional test of switch and electronics is carried out by means of a small permanent magnet.

Standard features

  • Specially designed for high level detection in cargo tanks on chemical and oil product tankers
  • Long experience (delivered on ships since 1979)
  • Meets IMO requirements concerning "Cargo Tank Overfill Protection System"
  • Made of acid resistant AISI 316 steel and PTFE (Teflon)
  • The level switch is continuously monitored
  • Solid-state design – no moving parts
  • Intrinsically safe installation
  • Test possibilities on switch unit
  • Intelligent sensor with self-diagnostics
  • Suitable for JIS B2220 size 100 5K adapter


  • EC-Type: TÜV 13 ATEX 124272X
  • IECEx: IECEx TUN 13.0030X
  • Approvals: DNV, ABS, BV, LR

Technical specifications

  • Power supply: 24 VDC (10 to 28 V)
  • Output signal: 4 to 20 mA, Normal = 8 mA, Alarm > 12 mA
  • Accuracy: ±1.0 cm
  • Type of protection: IP67 (housing)
  • Vibration: IACS E10 (max. 0.7g)
  • EMC: IACS E10
  • Operating temp.: -45 to 85°C (T4) / 70°C (T5)
  • Weight: Depends on sensor length (i.e. 10kg for double 1m sensor)
  • Material: Acid resistant steel AISI316 and PTFE (Teflon)
  • Connection: 2-wire 2.5 mm2
  • Cable: Ø8-20.5 mm2
  • Safety parameters: Ui = 28.0, VDCIi = 150 mA, Pi = 0.85 W, Ci = 21.2 nF, Li = negligible
  • Ex classification: II 1 G Ex ia IIC T4…T5 Ga

Related publications (PDF)

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