Article number: 70 921
  • The HIG91, HIG92, HIG93, and HIG94 series are a series of insulation monitoring devices for industrial isolated systems (IT systems).
  • The maximum operating voltage of the IT system is 275 V AC. This voltage can be increased up to 6 kV when using coupling devices from the TL series.
  • IMD with one Ran error level (HIG91, HIG92 series) or monitors with two error levels (HIG93, HIG94 series) are available.
  • As standard, the IMD measure RF in the range of 5 kΩ to 900 kΩ (HIG91, HIG93 series), alternatively in the range of 200 kΩ to 5 MΩ (HIG92, HIG94). Special IMDs are also available for different measuring ranges of insulation resistance.
  • IMDs are equipped with digital processing of the measured signal, which offers the user numerical information about the measured insulation resistance.
  • IMDs are designed with independent power supply. That means that these insulation monitors can be powered from a different system than the one they measure. This has the significant effect that the IMDs are able to measure even de-energized system.
  • The power supply of the device is AC as standard, for a nominal voltage of 230 V to 110 V / 50 Hz. However, versions with a 24 V DC supply are also available.
  • All IMDs are equipped with a digital bus, which allows information to be transmitted to the master system. For signaling of the IMD status, panels from the MDS-D series can also be used (variant with RS485).
Monitored IT power supply system type according to IEC 61557-8 AC
Measuring range of insulation resistance RF 1 000 ÷ 51 000 kΩ
Adjustable range of critical insulation resistance Ran 1 000 ÷ 51 000 kΩ
Number of insulation resistance fault levels (Ran)
Rated voltage of monitored IT system (AC) Un 275 V
IMD power supply From measured IT system, From independent power source
Nominal supply voltage AC Us 90 ÷ 265 V
Nominal supply voltage DC Us 90 ÷ 370 V
Power consumption P 5 VA
Measuring voltage Um 25 V
Measuring current Im < 1.2 mA
Measuring input’s internal impedance Zi > 2 000 kΩ
Measuring accuracy ± 10 %
Electrical strength against internal circuits 3 750 V
Equipped with display Yes (OLED technology)
Supported module of distant signalisation (MDS) MDS-D, MDS-DELTA
Communication interface for user RS485 bus
Communication protocol ISOLGUARD, PROFIBUS
External control inputs Test start
Housing material Polyamid PA6, UL94 V-0
Degree of protection of front panel IP40
Degree of protection except the front panel IP20
Operating temperature ϑ - 10 ÷ 60 °C
Protection class according to IEC 61140 II
Recommended cross-section of connected conductors S 1 mm2
Installation On DIN rail 35 mm
Modular width 2
Use for traction No
Operating position Any
Operation type Permanent
Quick contact
Ing. Aneta Sčebelová
 +420 494 942 314