Innovative technologies for safe handling of electrical power to achieve high availability

We offer you first-class quality and safety combined with global service and every support in resolving your monitoring problems.

ISOMETER® isoPV1685/isoPV1685PFR

ISOMETER® isoPV1685RTU/isoPV1685P

  • Application photovoltaic systems up to AC 1000V/DC 1500 V
  • Separately adjustable response values 200 Ω…1 MΩ
  • Automatic adaptation to the system leakage capacitance up to 2000 μF
  • Interface selectable RS-485 or Modbus

The device is used for insulation of large photovoltaic systems up to AC 1000 V/DC 1500 V designed as IT systems. The measurement method specially developed for slow voltage fluctuations (MPP tracking) monitors the insulation resistance even in systems equipped with large solar generator panels where extremely high system leakage capacitances against earth exist due to interference suppression methods. Adaptation to system-related high leakage capacitances also occurs automatically.

The device generates locating current pulses required for insulation fault location. That allows the localisation of the insulation fault using permanently installed or mobile insulation fault locators. 


Only device version isoPV1685P provide a locating current injector.

  • Insulation monitoring of large-scale photovoltaic systems
  • Measurement of low-resistance insulation faults
  • Separately adjustable response values Ran1 (alarm 1) and Ran2 (alarm 2) (both 200 Ω…1 MΩ) for prewarning and alarm. Ran1 ≥ Ran2 applies.
  • Automatic adjustment to high system leakage capacitances up to 2000 μF, selectable range
  • Connection monitoring of L+, L- for reverse polarity (DC only)
  • Integrated locating current injector up to 50 mA (isoPV1685P only)
  • Device self test with automatic message in the event of a fault
  • Alarm relays separately adjustable for insulation fault 1, insulation fault 2
  • CAN interface to output measured values, statuses and alarms
  • RS-485 interface
    – isoPV1685P: BMS bus, e.g. to control the insulation fault location
    – isoPV1685RTU: BMS bus or Modbus (can be switched using the DIP switch)
  • μSD card with data logger and history memory for alarms


  • Large PV systems designed as IT systems up to AC 1000 V*/DC 1500 V
    * Not for UL applications

ISOMETER® isoPV1685RTU/isoPV1685P Variant(s)

TypeResponse value rangeSupply voltage UsNominal system voltage UnArt. No.
isoPV1685RTU-425200 Ω…1 MΩDC 18…30 VAC 0…1000 V/DC 0…1500 VB91065603
isoPV1685P-425200 Ω…1 MΩDC 18…30 VDC 0…1500 VB91065604

Downloads for ISOMETER® isoPV1685RTU/isoPV1685P

CE Declarations of conformity isoXX1685 124.6 KB 2022/08/12 06:17:2512.08.2022 06:17:25
Manuals isoPV1685/isoPV1685PFR Appendix A 494.6 KB EN2019/05/13 10:31:5313.05.2019 10:31:53D00007
Manuals isoPV1685RTU/isoPV1685P 2.7 MB DE2021/10/08 09:08:4108.10.2021 09:08:41D00007
Manuals isoPV1685RTU/isoPV1685P 2.6 MB EN2021/10/08 09:08:5508.10.2021 09:08:55D00007
Datasheets isoPV1685RTU/isoPV1685P 627.9 KB DE2021/10/08 09:07:5308.10.2021 09:07:53D00007
Datasheets isoPV1685RTU/isoPV1685P 645.3 KB EN2021/10/08 09:08:0608.10.2021 09:08:06D00007
Datasheets isoPV1685RTU/isoPV1685P 525.5 KB ES2021/09/03 10:06:2103.09.2021 10:06:21D00007
Quickstarts isoPV1685RTU/isoPV1685P 1.2 MB DE2021/10/08 09:09:1208.10.2021 09:09:12D00007
Quickstarts isoPV1685RTU/isoPV1685P 1.2 MB EN2021/10/08 09:09:1208.10.2021 09:09:12D00007