iso685-x-B_D00177_07_M_XXEN/07.2019
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Special functions for coupled IT systems
11. Special functions for coupled IT systems
11.1 Particularities when monitoring coupled IT systems
When using ISOMETER®s in IT systems, make sure that only one active ISOMETER® is con-
nected in each interconnected system. If several ISOMETER®s are to be connected to the
IT system, ensure that only one ISOMETER® is active in the IT system via system isolation
using the digital input or Ethernet (ISOnet function).
If IT systems are interconnected via coupling switches, make sure that ISOMETER®s not
currently used are disconnected from the IT system and deactivated.
IT systems coupled via diodes or capacitances may also influence the insulation monito-
ring process so that a central control of the different ISOMETER®s is required.
11.2 System isolation via digital input
with two coupled systems
Via the X1 connector, the ISOMETER® can be isolated from the IT system and the measur-
ing functions can be deactivated. Therefore, the function of the digital input in use has to
be set to "Device inactive".
If the digital input used for this function is selected, the connectors "L1/+", "L2", "L3/-" are
deactivated via internal system isolating switches, the measuring function stops and the
following message appears on the display: "Device inactive. Device separated".
Stored fault messages are reset when the cause of the fault has been eliminated (RESET
function).
In order to deactivate the ISOMETER® iso685-x-B via one of the dig-
ital inputs, the coupling switch must have a free contact.
IT-System 1
IT-System 2
BCOM
Adr. 1
BCOM
Adr. 2
If the digital input is no longer selected, first the connection to the IT system is restored
and afterwards, an entirely new measuring cycle for the insulation monitoring starts. This
function can be used to disconnect the second ISOMETER® selectively in coupled IT sys-
tems via the auxiliary contact of the coupling switch.
11.3 System isolation via ISOnet
The ISOnet function ensures via an Ethernet connection that only one ISOMETER® of the
interconnection is active when several ISOMETER®s are connected to an IT system.
For several ISOMETER®s to be able to measure in the same ISOnet interconnection, the
settings for the BCOM system name and the BCOM subsystem have to be the same. Only
the device address has to be different. If this is not taken into account, the ISOnet function
will not work.
If the ISOnet function is deactivated in an ISOMETER® in an ISOnet interconnection, it will
measure continuously and will not forward measuring commands to the next device in
the interconnection.
In comparison to a solution with coupling switches and function input, the response time
will be extended because the measurement in the IT system is not carried out conti-
nuously.
The addresses of the ISOMETER®s in the ISOnet interconnection can be selected at will.
The addresses do not have to be subsequent but they have to differ from each other.
If in addition to the ISOnet interconnection the digital inputs are wired and a device is
deactivated via a digital input, the device will forward the measuring authorisation until
the signal at the digital input disappears. Afterwards, it participates again in the measu-
ring interconnection.
Configuration
Maximum number of devices in an ISOnet interconnection: 20 devices
The IP address of the standard gateway must suit the subnet mask, so that
the ISOnet function can operate correctly.
