3
17.03.21 en / 371A
Function Diagram
Connection Terminals
Terminal designation
Signal description
A1(+), A2
Auxiliarx voltage AC or DC
L(+), L(-), VSG1, VSG2
Connection for coupling device
PE1, PE2
Connection for protective conductor
X1, X2
Control input
(combined external Test- and Reset-input
with additional Stop of the measuring
function)
Y1(+), Y2
Semiconductor output (Open Collector) with
PWM-signal to indicate the actual insulation
resistance
11, 12, 13
Alarm signal relay K1(1 changeover contact)
21, 22, 23
Device fault indicator relay K2
(1 changeover contact)
Circuit Diagram
Flashing Codes Status LED
Programming/setting of parameters/set-up of the insulation monitor
All settings are made via 3 rotational switches on the front of the device.
To avoid unauthorised manipulation of the settings, the unit has a sealable
transparent cover on the front.
The response value for Alarm is adjusted by the first rotary switch "R
A
".
The second rotary switch "Rel." is used to alter the relay function. If set to
"n.c." the output is de-energised on trip, If set to "n.o." the output is energised
on trip. In addition this rotary switch has 2 sections. If the setting is in the
section, the broken wire detection in the measuring circuit is activated, if the
setting is on the second section, the broken wire detection in the measuring
circuit is de-activated.
The third rotational switch selects "UN" selects the voltage system connection
and manual or auto reset it has also 2 sections. In section one the unit is
on auto reset, in section 2 it is on manual reset. Changes of the setting the
unit accepts immediately without restart.
If the second or third rotary switch is in an undefined position, the unit
changes to "parameter failure" (see description under "behaviour at
parameter failures").
Function
X1 X2
11 12 14 21 22 24
PE1
PE2
A2
A1(+)
L(+)
VSG1
VSG2
L(-)
22
12
L(+) L(-)
24
14
21
PE2
11
PE1
U
H
Y1
(+) Y2
M12297_a
extended
test
self test
connection failure
measuring ciruit L(+)/L(-)
connection failure
protective conductor PE1/PE2
LE
D
-c
ol
ou
r:
or
an
ge
LE
D
-c
ol
ou
r:
re
d
internal
system error
M12295
measuring function
disabled
Parameterization
error
t
Manual reset
Alarm
Pr
e-Alarm
Hysteresis function
Earth fault
E
R
A
R
Open circuit operation
Open circuit operation
De-energized on trip
De-energized on trip
UH
M12292
Reset
11-14
11-14
11-14
11-14
11-12
11-12
11-12
11-12
t
t
Semiconductor Output (PWM output)
Broken wire detection:
If the PWM-signal is continuously high,
a broken wire is detected.
Short circuit detection:
If the PWM-signal is continuously low, the
semiconductor may have a short circuit.
M12318
pulse break
min. 1s
0
0
0
5ms
3000ms
3000ms
1000ms
3000ms
2000ms
minimum pulse length 5ms (corresponds to 5k )
pulse length 1000ms (
1M )
corresponds to
maximum pulse legth 2000ms (
2M )
corresponds to
