Guided radar (TDR) level transmitter for liquids at high temperature and pressure

  • Continuous level and interface measurement in boilers, reactors and separators
  • With dynamic gas-phase compensation for boiler applications (in preparation)
  • Measuring range: 0.6…60 m / 2…197 ft
  • -50…+315°C; -58…+599°F; -1…320 barg; -14.5…4641 psig
  • Icon/Logo Security Integrity Level 2 (SIL 2)

OPTIFLEX 8200 C– Compact version with Ø4 mm / 0.16" single cable probe

OPTIFLEX 8200 Guided radar (TDR) level transmitter – Compact version with extension and single cable

The OPTIFLEX 8200 is a 2-wire guided radar level transmitter based on the Time Domain Reflectometry (TDR) technology. It is designed for level and interface measurement under extreme conditions in the power, oil and gas industries. Using an algorithm called "Dynamic Gas-phase Compensation (DGC)", the device measures accurately and without increased blocking distance the level of products in processes where the composition of the gas above the product can change suddenly (e.g. in steam boilers).

For high safety requirements in applications with dangerous media, the OPTIFLEX 8200 features a single or double ceramic process seal system. Various converter and electronic versions like a remote converter or a sensor extension facilitate the access to the device. The level transmitter has approvals for use in hazardous areas.

Product highlights

  • Designed for steam boilers
  • Single or double ceramic process seal system for demanding process conditions
  • Patented Dynamic Gas-phase Compensation (DGC) for coaxial probes (in preparation)
  • Various converter and electronic versions to facilitate access to the device:
    • Available as compact version (C) or with remote converter (F) up to 100 m / 328 ft
    • Sensor extension with compact version (S) up to 15 m / 49.2 ft
    • Horizontal or vertical housing to suit every installation
  • Converter is rotatable and removable under process conditions and compatible with all process connections from previous KROHNE TDR models
  • Stainless steel housing for corrosive environment
  • Weather protection - protects the converter in extreme weather conditions
  • Diagnosis functions according to NAMUR  NE 107
  • NACE design MR 0175 (ISO 15156), MR 0103 (ISO 17945) / ASME B31.3
  • SIL 2/3 (in preparation)
  • ±2 mm /±0.08" accuracy
  • Real-time clock for event logging
  • 3-year warranty

Typical applications


  • Level and interface measurement in applications with high temperature or pressure conditions up to +315°C / +599°F or 320 barg / 4641 psig
  • Level applications involving industrial low pressure (LP) boilers
  • Installation on magnetic level indicators (MLI) or in bypass chambers

Chemical and petrochemical industry

  • Ethylene, fertilizer (urea), chlorine, resin, paint, ink

Oil and gas

  • Liquefied petroleum gas (LPG), hydrocarbons
  • Separators of gas and oil
  • Distillation towers

Power generation

  • Steam boiler (alkaline drum and feed water)

Technical data

Measurement principlesGuided radar
Level measurement typeContinuous measurement
Measured mediaLiquid/liquid interface, Liquids
Contact to measured mediumYes
Interface measurementYes
Probe diameter
  • Single cable Ø4 mm / 0.16"
  • Single rod Ø8 mm / 0.32"
  • Single rod Ø8 mm / 0.32" (segmented)
  • Coaxial Ø42 mm / 1.65"
Probe length0.6...60 m
1.97...196.85 ft
Measuring range (liquids)0.6…60 m
1.97…196.85 ft
Process pressure (relative)-1… 320 barg
-14.5… 4641 psig
Process temperature-50…+315°C
Wetted partsAustenitic stainless steel (1.4404/316L), Austenitic alloy (2.4602/Alloy 22), Ceramic
Process sealsCeramic, Ethylene propylene diene monomer (EPDM), Fluorocarbon-based synthetic rubber (FKM/FPM), Kalrez® 7075
Accuracy (liquids)±2 mm


Certificates/Approvals ExATEX, cQPSus, IECEx, INMETRO, NEPSI
Certificates/Approvals SafetySIL2
Certificates/Approvals OthersNACE
Ingress protectionIP66/68, NEMA4X/6
NAMUR complianceNE 107, NE 21, NE 43, NE 53


Digital outputsHART®
Discrete outputsRelay
Analogue outputs4…20 mA

Process connections

Flange connectionsDN25…200
Thread connectionsMale:
G1, G1½
1 NPT, 1½ NPT