Bender ISOMETER IRDH375, Manual

Page: 24 / 100

Function
25 IRDH375_D00124_05_M_XXEN/01.2020
3.5 Additional functions IRDH375B
Current output for external measuring instrument
The current output of IRDH375B provides 0(4)…20 mA. The current output is
galvanically isolated from the device electronics and the RS-485 interface. The
ISO SETUP menu, on page 43, allows to switch over between 0…20 mA and
4…20 mA.
Real-time clock
The real-time clock serves as a time base for the memory and self test func-
tions. At first, the correct time and date must be set in the menu
"ISO ADVANCED". If time and date are not set, a "C" (clock) is flashing in the
standard display. In the event of a supply voltage failure, time and date will be
stored for at least thirty days.
If the 24 h selftest is activated in the "ISO ADVANCED" menu, a special time of
day can be selected for the execution of the self test in the menu "TEST: 12:00".
Then a self test will be started automatically once a day exactly at the preset
time. If the 1 h auto test has been selected, the self test is automatically carried
out every full hour.
Interconnected IT systems
When using ISOMETER®s in IT systems, make sure that only one active
ISOMETER® is connected in each interconnected system. If IT systems are in-
terconnected via coupling switches, make sure that ISOMETER®s not currently
used are disconnected and deactivated via a control system. IT systems cou-
pled via diodes or capacitances may also influence the insulation monitoring
process. Hence, also in this case a central control of the different ISOMETER®s
is required.