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  • Offline monitoring
  • 3 insulation levels are monitored
  • Modbus TCP
  • Reduced measuring voltage

The ISOMETER® isoNAV685-D-B is an insulation monitoring device for IT systems in accordance with IEC 61557-8. It is universally applicable in de-energised TN, TT or IT systems.

  • Features
  • Applications
  • Accessories
  • Ordering information
  • Downloads
  • ISOMETER® to monitor the insulation resistance in de-energised systems.
  • Automatic adaptation to the existing system leakage capacitance.
  • AMPPLUS measurement method
  • An adjustable response value in the range 10 kΩ…1 MΩ (factory setting = 50 kΩ).
  • High-resolution graphic LC display for excellent readability and recording of the device status.
  • Earth connection monitoring.
  • Automatic device self test.
  • Graphical representation of the insulation resistance over time (isoGraph)
  • History memory with real-time clock (buffer for three days) for storing 1023 alarm messages with date and time.
  • Freely programmable digital inputs and outputs.
  • Remote setting via the Internet or Intranet (Webserver/Option: COMTRAXX® Gateway).
  • Worldwide remote diagnosis via the Internet.
  • BCOM, Modbus TCP and web server.
  • Monitoring of de-energised loads and systems


Mandatory accessories for ISOMETER® isoNAV685-D-B

Type designationArt. No.
A set of screw terminals*B91067901
A set of push-wire terminalsB91067902
Enclosure accessories (terminal cover, 2 mounting clips)*B91067903
* included in the scope of delivery
Possible measuring instruments on request!


Variants of ISOMETER® isoNAV685-D-B

TypeNominal system voltage range UnSupply voltage USArt. No.
isoNAV685-D-BofflineAC 24…240 V; 50…400 Hz /
DC 24…240 V

Downloads for ISOMETER® isoNAV685-D-B



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