15
RCMA420-DM_D00060_02_M_XXEN/06.2016
3. Function
3.1
Device features
AC/DC sensitive residual current monitor Type B according to IEC
62020 and IEC 60755
Two separately adjustable response ranges (prewarning, alarm)
Adjustable switching hysteresis
R.m.s. value measurement
Start-up delay
Measured value display via multi-functional LC display
Alarm indication via LEDs (AL1, AL2) and analogue interface
Password protection against unauthorized parameter changing
Fault memory function can be switched off
CT connection monitoring
Manual device and CT self test using true test current
3.2
Function
Once the supply voltage
U
s
is applied, the start-up delay is activated. Residual
current measurement takes place via an external measuring current transfor-
mer of the W20AB…W60AB(P) series. The currently measured value is shown
on the LC display. In this way any changes, for example when circuits are con-
nected to the system, can be recognized easily.
If the measured value exceeds one or both response values, the alarm LEDs
AL1 / AL2 light up. If the residual current falls below the release value (respon-
se value minus hysteresis), the alarm LEDs AL1/AL2 go out. If the fault memory
is activated, the LEDs light until the
reset button R
is pressed or until the sup-
ply voltage is interrupted.
The device function can be tested using the
test button T
.
The
parameterization
of the device can be carried out via the LC display and
the function keys integrated in the front plate and can be password-
protected.
