This device belongs to the Vigilohm range designed for monitoring unearthed power supplies (IT systems) in accordance with installation and product standards. According to the standards, it is recommended to equip your systems with insulation monitoring devices (IMD). This device is suitable for monitoring pure AC systems of limited size and low interference. It measures the network insulation resistance by injecting a direct current between the network and earth. The configuration depends on the installation. The settings are available on the front panel of the device. The settings concern alarm and pre-alarm thresholds. It is equipped with a manual autotest. If the system insulation resistance falls below the set threshold, i.e. there is a ground fault, an alarm is triggered via the IMD output relay. Once no more faults are detected, the alarm is canceled and the alarm relay returns to normal. This product can be installed on a DIN rail.