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ISOMETER® iso685-…-P

ISOMETER® iso685-…-P

  • Predefined measurement profiles
  • Reliable measurement of insulation resistance, voltage, capacitance and frequency
  • Integrated web server
  • Modbus TCP/RTU
  • History memory

The ISOMETER® is an insulation monitoring device for IT systems in accordance with IEC 61557-8 and IEC 61557-9. It is universally applicable in AC, 3(N)AC, AC/DC and DC systems. AC systems may include extensive DC-supplied loads (such as rectifiers, inverters, variablespeed drives).

In combination with the insulation fault locators of the EDS44x series or the appropriate measuring current transformers, an insulation fault location system can be set up with the iso685-…-P.

Device variants
iso685-D-P: The device variant iso685-D-P features a high-resolution graphic LC display and operating controls for direct operation of the device functions.
iso685-S-P: The device variant iso685-S-P is operated via the detached operating unit FP200.
Option "W": The ISOMETER®s with and without integrated display are available for extreme climatic and mechanical conditions.

  • Features
  • Applications
  • Accessories
  • Ordering information
  • Downloads
  • ISOMETER® for IT AC systems with galvanically connected rectifiers or inverters and for IT DC systems (IT = unearthed systems)
  • 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
  • High-resolution graphical LC display
  • 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 or 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 of certain parameters via the Internet (web server/Option; COMTRAXX® gateway)
  • Worldwide remote diagnosis via the Internet (made available by Bender Service only)
  • RS-485/BS (Bender sensor bus) for communication with other Bender devices
  • ISOnet: Internal separation of the ISOMETER® from the IT system to be monitored (e.g. if several IT systems are interconnected)
  • BCOM, Modbus TCP/RTU and web server
  • Locating current injection for selective insulation fault location
  • Indication of the insulation faults selectively located by the EDS system
  • Parameter setting of EDS systems
  • Customer-specific texts for each measuring channel

  • Insulation fault location in AC, 3AC and DC IT systems
  • Up to 12 measuring current transformers of the W…, WR…, WS… measuring current transformer series can be connected
  • Response sensitivity insulation fault location: EDS440 2…10 mA; EDS441 0.2…1 mA
  • Response sensitivity residual current measurement: EDS440 100 mA…10 A; EDS441 100 mA…1 A
  • Communication of the components via BS bus (RS-485) or BB bus
  • 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 switch-mode power supplies
  • IT systems with high leakage capacitances
  • Installations with insulation fault location


Mandatory accessories for ISOMETER® iso685-…-P

Type designationArt. No.
A set of screw-type terminals*B91067901
A set of push-wire terminalsB91067902
Enclosure accessories (terminal cover, 2 mounting clips)*B91067903
Transparent cover 144x72 (IP65) for FP200**B98060005
BB bus 6TE connector***B98110001
* included in the scope of delivery
** If the “transparent front cover 144x72 (IP65)” is used, the cutout in the control cabinet must be increased in height from 66 mm to 68 mm (+ 0.7/-0 mm).
*** Necessary for the connection of the ISOMETER®s with an EDS44…-S


Optional accessories for ISOMETER® iso685-…-P

Insulation fault locators
TypeSupply voltage US*Response valueArt. No.
EDS440-S-1AC/DC 24…240 V2…10 mAB91080201
EDS440W-S-1AC/DC 24…240 V2…10 mAB91080201W
EDS440-L-4AC/DC 24…240 V2…10 mAB91080202
EDS440W-L-4AC/DC 24…240 V2…10 mAB91080202W
EDS441-S-1AC/DC 24…240 V0,2…1 mAB91080204
EDS441W-S-1AC/DC 24…240 V0,2…1 mAB91080204W
EDS441-L-4AC/DC 24…240 V0,2…1 mAB91080205
EDS441W-L-4AC/DC 24…240 V0,2…1 mAB91080205W
EDS441-LAB-4AC/DC 24…240 V0,2…1 mAB91080207
EDS441W-LAB-4AC/DC 24…240 V0,2…1 mAB91080207W

Relay module
TypeSupply voltage USArt No.
IOM441-SDC 24 VB95012057
IOM441W-SDC 24 VB95012057W

Variants of ISOMETER® iso685-…-P

TypeNominal system voltage range UnSupply voltage USDisplayOption WArt. No.
iso685-D-PAC 0…690 V; 1…460 Hz
DC 0…1000 V
AC 24…240 V; 50…400 Hz
DC 24…240 V
iso685W-D-P*AC 0…690 V; 1…460 Hz
DC 0…1000 V
AC 24…240 V; 50…400 Hz
DC 24…240 V
3K23, 3M12
iso685-S-P + FP200AC 0…690 V; 1…460 Hz
DC 0…1000 V
AC 24…240 V; 50…400 Hz
DC 24…240 V
iso685W-S-P + FP200W*AC 0…690 V; 1…460 Hz
DC 0…1000 V
AC 24…240 V; 50…400 Hz
DC 24…240 V
3K23, 3M12

Device variants

iso685-D-P: This device variant ISOMETER® iso685-D-P features a high-resolution graphic LC display and operating controls for direct operation of the device functions. It cannot be combined with an FP200.
iso685-S-P: This device variant ISOMETER® iso685-S-P features neither a display nor operating controls. It can only be used in combination with the FP200 and it is operated via this front panel.
Option "W": The ISOMETER®s with and without integrated display are available with option „W“ for extreme climatic and mechanical conditions (ISOMETER® iso685W-D-P and iso685W-S-P).

Downloads for ISOMETER® iso685-…-P



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