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ISOMETER® iso1065 (IRDH1065)

  • Straightforward, fast replacement for the IRDH 1065
  • Monitor insulation resistance for IT systems and forewarn of cable degradation
  • Flexible and adjustable response value ranges
  • Customised pre-set threshold values
  • Two device variants available

The ISOMETER® iso1065 is an insulation monitoring device designed primarily for use in oil and gas applications monitoring the degradation in subsea cables and umbilicals. The device is suitable for monitoring insulation resistance on unearthed IT systems.

The iso1065 Line Insulation Monitor (LIM) is a direct replacement device for the obsolete IRDH 1065, designed to provide a quick and easy upgrade that requires no additional equipment during installation.

There are two variants of the device, the iso1065 and the iso1065-M with analogue output.

The device has an LCD user interface to provide an accurate system overview and allow simple and intuitive parameterisation of all connected devices.


  • Monitoring the insulation resistance for ungrounded systems up to 1000 V
  • Measurement of system voltage with undervoltage and overvoltage detection
  • Measurement of DC system voltages to earth
  • Automatic adaptation to the system leakage capacitance
  • Selectable start-up delay, response delay and delay on release
  • Two separately adjustable response values
  • Alarm signaling via LEDs, a display and alarm relays
  • Automatic device self-test with connection monitoring
  • Measured value indication via LC display
  • Password protection to prevent unauthorized parameter changes
  • RS-485 communications (galvanically separated) including the following protocols:
    - Modbus RTU
    - BMS interface (Bender measuring device interface) for data exchange with other Bender components
    - IsoData (for continuous data output)
  • Components developed in compliance with:
    - DIN EN 61557-8 (VDE 0413-8): 2015-12/Ber1: 2016-12
    - DIN EN 50155: 2018-05
    - EN 45545-2:2016
    - IEC 61557-8: 2014/COR1: 2016
    - EN61373 cat I class B


  • Designed for use in subsea applications such as cables and umbilicals

ISOMETER® iso1065 (IRDH1065) Variant(s)

Featureiso1065 / iso1065-M
AC/DC systems
Additional overvoltage and undervoltage protection
Measurement of DC voltage to earth
Maximum system leakage capacitance150 μF
Selectable start-up/response/release delay
Two separately adjustable response value ranges10...500 kΩ (Alarm 1, Alarm 2)
Alarm signalling via LEDs
Measured value indication via a multifunctional LC display
Selectable N/C or N/O relay operation✔ via termination/user interface
Password protection
Analogue outputiso1065-M variant
•Voltage output DC 0…10 V, load ≥ 20 kΩ
•Current output DC 0/4…20 mA, load ≤ 130 Ω
•Current output DC 0…400 μA, load ≤ 3 kΩ
RS485iso1065 variant only
Part numbersiso1065 or iso1065--M

Downloads for ISOMETER® iso1065 (IRDH1065)

CE Declarations of conformity IRDH1065 84.2 KB 2022/08/12 06:17:2512.08.2022 06:17:25
Datasheets iso1065 346.2 KB EN2020/11/10 13:03:3510.11.2020 13:03:35D00435
Product Brochures iso1065 2.0 MB EN2020/10/19 15:42:5019.10.2020 15:42:50