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  • Predefined measurement profiles

  • Reliable measurement of insulation resistance

  • Integrated web server / Modbus TCP/RTU

  • Automatic insulation fault location

  • 12 measuring channels for measuring current transformers

Insulation monitoring devices Iso685-x-x continuously monitor the insulation resistance of IT systems (unearthed systems) and issue an alarm if the value falls below a response value.

To obtain a measurement, the device has to be connected between the IT system and the protective earth conductor (PE). A measuring current is superimposed onto the system which is detected and evaluated by a measuring circuit. Insulation monitoring devices detect deteriorations of the insulation level at an early stage and in a reliable way.

The insulation fault locators ISOSCAN® EDS440 are used in connection with the ISOMETER® iso685-D-P or the locating current injector PGH to locate insulation faults in unearthed power supply systems (IT systems).

They detect locating current signals generated by the insulation monitoring device iso685-D-P or IRDH575 or the locating current injector PGH and evaluate them correspondingly. Up to 12 measuring current transformers can be connected to an EDS440. In total, up to 21 insulation fault locators can be connected via an RS-485 interface (BS bus protocol) and thereby up to 252 outgoing circuits can be monitored.



  • ISOMETER® for IT AC systems with galvanically connected rectifiers or inverters and for IT DC systems (IT = unearthed systems).

  • Nominal system voltage Un expandable via coupling devices

  • Automatic adaptation to the existing system leakage capacitance.

  • Combination of AMPPlus and other profile specific measurement methods.

  • Two separately adjustable response value ranges of 1 kΩ…10 MΩ for alarm 1 and alarm 2

  • High-resolution graphic LC display for excellent readability and recording of the device status.

  • Connection monitoring (monitoring of the measuring lines).

  • 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.

  • Current and voltage output 0(4)…20 mA, 0…400 μA, 0…10 V, 2…10 V (galvanically separated) which is analogous to the measured insulation value of the system.

  • Freely programmable digital inputs and outputs.

  • Remote setting via the Internet or Intranet (Webserver/Option: COMTRAXX® Gateway).

  • Worldwide remote diagnosis via Internet.

  • RS-485/BS (Bender sensor bus) for communication with other Bender devices

  • BCOM, Modbus TCP/RTU and web server

EDS System

  • Modular design, therefore easily adjustable to the given circumstances

  • Measuring current transformers available in various sizes and versions

  • CT connection monitoring

  • 12 measuring channels for measuring current transformer series CTAC…, WR…, WS…

  • Fault memory behaviour selectable

  • Configuration possibilities enable individual adjustments

  • Up to 21 EDS insulation fault locators in the system, 252 measuring channels


  • AC, DC or AC/DC main circuits

  • AC/DC main circuits with directly connected DC components, such as rectifiers, converters, variable-speed drives

  • UPS systems, battery systems

  • Heaters with phase control

  • Systems including switched-mode power supplies

  • IT systems with high leakage capacitances

  • Insulation fault location in AC, 3AC and DC IT systems

  • Main circuits and control circuits in industrial plants and ships

  • Diode-decoupled DC IT systems in power plants

  • Systems for medical locations

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