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RCMA423-DM_D00064_03_M_XXEN/06.2017
3. Function
3.1 Device features
AC/DC sensitive residual current monitor type B acc. to
IEC 62020 and IEC/TR 60755
Two separately adjustable response value ranges (prewarning, alarm)
Adjustable switching hysteresis
r.m.s. value measurement
Start-up delay
Measured value indication via multi-functional LCD
Alarm indication via LEDs (AL1, AL2) and analogue interface
Password protection to prevent unauthorised parameter changes
The fault memory can be deactivated
CT connection monitoring
Manual self test of device and transformer with a genuine test current
3.2 Function description
After connecting the supply voltage U
s
, the start-up delay is active. The resi-
dual current is measured via an external measuring current transformer from
the W20AB…W210AB type series. The currently measured insulation resis-
tance is indicated on the LC display. This way any changes, for example when
outgoing circuits are connected to the system, can be recognised easily.
If the set response values are exceeded, the alarm LEDs AL1/AL2 light up. In
addition, a proportional voltage or current signal is emitted by the analogue
output that has been preselected via the menu. Refer also to "chapter 3.2.13
Interface".
If the residual current falls below the release value (response value minus hys-
teresis), the alarm LEDs AL1/AL2 go out. If the fault memory is activated, the
LEDs stay lit until the reset button R is pressed or until the power supply is in-
terrupted.
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