Insulation Fault Location; Assignment Of The Alarm Relays K1, K2, K3; Deactivating The Device; Measured Value Transmission - Bender ISOMETER iso1685DP-425 Manual

Function
An insulation fault between the IT system and earth closes the measuring circuit. If the in-
sulation resistance between system and earth falls below the set response values R
and R (response value R can be set equal or higher than R
an2 an1
relays K1 (11, 12, 14) or K2 (21, 22, 24) switch. Detected insulation faults are signalled to
other bus devices via the BMS bus. In addition, the alarm LEDs ALARM 1 or ALARM 2 light
up.

3.3.2 Insulation fault location

For insulation fault location, a suitable locating current is superimposed onto the faulty
IT system with which insulation fault locators of the EDS... series can locate insulation
faults. The ISOMETER® features an internal locating current injector with I
I
L
2 s 4 s
Pulse sequence of the internal locating current injector for insulation fault location
Malfunctions due to excessive locating current on sensitive system
parts! The locating current flowing between the IT system and earth can
cause controller faults in sensitive parts of the system, such as the PLC or
CAUTION relay. Ensure that the level of the locating current is compatible with the
system to be monitored.
If the "Auto EDS function" is enabled, the ISOMETER® starts the insulation fault location
after the value has fallen below the response values R
sulation fault location, the "PGH ON" LED signals the locating current pulse.
During the insulation fault location process, the measurement of the insulation resist-
ance is deactivated and the coupling is disconnected from the mains. If during the insu-
lation fault location the locating current falls below the value measurable by the EDS, the
insulation fault location is terminated by the ISOMETER®.

3.3.3 Assignment of the alarm relays K1, K2, K3

K1 switches when the value falls below the alarm response value R
ance).
K2 switches when the value falls below the alarm response value R
ance).
K3 switches in the event of a device error or a connection fault.
10
an1
), the associated alarm
an2
DC 50 mA.
L
2 s
4 s t
and R . When starting the in-
an1 an2
(insulation resist-
an1
(insulation resist-
an2
Function

3.3.4 Deactivating the device

When the device is deactivated, the coupling unit of the device is galvanically isolated
from the system being monitored.
The device does not measure the insulation resistance, the message "Device inactive" ap-
pears on the display. The IT system is NOT being monitored!
The device uncouples itself from the system to be monitored through an internal system
isolating switch.
Activation or deactivation is done via
• a digital input
• the menu item Alarm settings
• the BMS bus and Modbus RTU
The standby mode of the ISOMETER®, for example, enables application in coupled sys-
tems, since in interconnected systems only one insulation monitoring device may be
connected.

3.3.5 Measured value transmission

All recorded measured values, operating messages and alarms are made available via the
BMS bus or Modbus RTU.

3.4 History memory

All warnings, alarms and device errors are stored in the internal history memory with date
and time stamp. The time the event started, the time of acknowledgement and the end
of the event are recorded. The history memory can be called up and reset via the device
menu (see "History" on page 38).

3.5 Self test

3.5.1 Self test after connection to the supply voltage

Once connected to the supply voltage, all internal measurement functions, the compo-
nents of the process control such as data and parameter memory as well as the connec-
tions to earth are checked. The self test is completed after approx. 60 s. Afterwards, the
normal measurement mode begins.
If a device error or a connection fault is detected, the corresponding alarm will be indicat-
ed in the display as well as via the alarm relay K3 (31-32-34). This relay operates continu-
ously in NC operation, i.e. a device error is signalled even in case of a complete device
failure.
isoxx1685Dx-x25_D00272_06_M_XXEN/04.2020