iso1685DP_D00272_02_M_XXEN/07.2017
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Function
3. Function
3.1 Features
• Insulation monitoring in extensive unearthed power supply systems up to
AC 1000 V/DC 1500 V
• Measurement of low-resistance insulation faults
• Separately adjustable response values
R
an1
(alarm 1) and
R
an2
(alarm 2)
(both 200 Ω…1 MΩ)
• Automatic adjustment to high system leakage capacitances up to 2000 μF,
selectable range
• Integrated locating current injector up to 50 mA
• Device self test with automatic message in the event of a fault
• Alarm relays separately adjustable for insulation fault 1, insulation fault 2 and device
error
• RS-485 interface (BMS bus), e.g. to control the insulation fault location.
• The device does not have a master function. It can only act as backup master.
• The integrated μSD card slot cannot be used. The device does not store any data on
the μSD card.
3.2 Product description
The ISOMETER® is an insulation monitoring device for IT systems in accordance with IEC
61557-8 and IEC 61557-9. It is applicable for use in AC/DC systems.
3.3 Function description
The insulation monitoring device ISOMETER® iso1685DP-425 continuously monitors the
entire insulation resistance of an IT system during operation and triggers an alarm when
the value falls below a preset response value. To obtain a measurement, the device has
to be connected between the IT system (unearthed system) and the protective earth con-
ductor (PE). A measuring current in the μA range is superimposed onto the system which
is recorded and evaluated by a microcontrolled measuring circuit. The measuring time
depends on the selected measurement methods, the system leakage capacitance, the in-
sulation resistance and possible system-related disturbances. In addition, it features an
integrated locating current injector for insulation fault location.
The response values and other parameters are set using a commissioning wizard or via
different setup menus using the device buttons and a high-resolution graphic LC display.
The selected settings are stored in a permanent fail-safe memory. Different languages
can be selected for the setup menus and the messages indicated on the display.
The device utilises a clock for storing fault messages and events in a history memory with
time and date stamp. The settings can be protected against unauthorised modifications
by a password.
The ISOMETER® cannot take over the master function. If there is no master in the system,
the device can act as a backup master and communicate with the slaves in the system.
Содержание ISOMETER iso1685DP
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