Process Control Instruments and Field Devices
SKU# (236)



  • Overview
  • Features
  • Specs
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EH Liquiphant FML621 Density Computer for vibronic measurement of density, reference density and concentration of liquids in conjunction with a Liquiphant switch. EExia, EExde and EExd explosion protection for use in hazardous areas. 4-20mA and Ethernet Outputs. ATEX, FM, CSA and IECEx approvals.

Part# with Options:        FML621-A11AAAAAB11
Price with Options:        Please Email us your request for quote   


(1) Approval for EH FML621
Display & Operation
(2) Display & Operation EH FML621
Power Supply
(3) Power Supply EH FML621
(4) Slot EH FML621
(5) Slot EH FML621
(6) Slot EH FML621
(7) Software EH FML621
Operation Language
(8) Operation Language EH FML621
(9) Communication EH FML621
Additional Option
(10) Additional Option EH FML621

  Availability 9 Days  ]


The density measuring line can be used in liquid media. It is used for the following purposes:

  • Density measurement
  • Intelligent medium detection
  • To calculate the reference density
  • To calculate the concentration of a liquid
  • To convert values to different units such as °Brix, °Baumé, °API etc.

In conjunction with Liquiphant M Density with electronic insert FEL50D, the Density Computer FML621 returns a continuous density measured value. Furthermore, values can be converted to Baumé, °Brix etc.

Additional software modules, such as determining the reference density, intelligent medium differentiation and concentration identification, support the user in monitoring the quality for example.

The tables for converting density to concentration must be provided by the customer.

Sensor versions with electronic insert FEL50D


Compact design, ideal for mounting in pipes and for installation in areas difficult to access


With extension pipe up to 3 m
Highly corrosion-resistant Alloy C4 (2.4610) is available for the tuning fork and process connection for applications in very aggressive liquids.


With polished tuning fork and easy-to-clean process connections and housings for food and pharmaceutical applications.


All the wetted parts are available with a wide range of coatings, such as enamel, PFA and ECTFE, and are thus suitable for use in very aggressive liquids.

International approvals certify use in hazardous areas.

Your Benefits
  • Measurement used directly in tanks or pipes without the need for additional pipework
  • Large number of process connections to choose from: universal usage
  • Integration of existing temperature measurements for temperature compensation
  • No mechanically moving parts: no maintenance, no wear, long operating life
  • Pump protection can be provided with the same process connection
  • Additional calculations, such as the concentration of a product, can be performed in the Density Computer FML621
  • The integrated data logger supports users with data during operation and servicing
  • Hygiene-compliant solutions with EHEDG and 3A approvals
Measuring principle

A piezoelectric drive excites the tuning fork of the Liquiphant M Density to its resonance frequency. If the density of the liquid medium changes, the resonance frequency of the tuning fork also changes. The density of the medium has a direct impact on the resonance frequency of the tuning fork. By storing specific medium properties and mathematic relations in the system, the exact concentration of the medium, for example, can be calculated.

Measuring Principle Vibration Density
Characteristic / Application Density Computer
Software offers modules for density, reference density, concentration of liquids and for a intelligent medium detection
Supply / Communication AC 90-253V
DC 20-36V
Ambient temperature -20...50°C
Output 4-20mA
Profibus DP
Certificates / Approvals ATEX
Options Mathscapabilities for further calculations
Specialities Configuration with ReadWin2000

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