Internal Connection Diagram - Mitsubishi Electric MELPRO-A Series Instruction Manual

2. RUN display (Self-monitoring function)
This relay monitors
circuit, and program data at all time. The RUN LED
(green) lights up in the normal condition.
In the abnormal condition, the RUN LED goes out and
the error message Ｅ ｒ ｒ
numerical display LED, with the output contact
locked.
3. Numerical display function
By switching the position of the indicator select
switch, following items can be displayed on the
numerical display LED.
①I current measurement
0
The display shows the value of zero-sequence
current. The display range is from 0.05A to 1.5A.
(If input current is less than 0.05A, the display
goes out. If input current is more than 1.5A, the
error message Ｏ.Ｆ. is displayed.)
②Pickup
When input zero-sequence current is greater than
or equal to the setting value, Ｉ. is displayed.
This function can be used for operation value tests.
③Setting value
It displays the setting condition of the relay
including I operation value and operating time
0
setting.
④Frequency setting
It displays the setting condition of frequency in
accordance with the setting switch of SW1.

Internal connection diagram

Z1
Level
I
0
assessment
Z2
P1
Auxiliary
power
Power supply
supply
P2
Continuous
monitoring
Power circuit
monitoring
a）MGR-A3V-R
control voltage, electric
is displayed on the
Operation
indicator
X0
RUN indicator
Output
X0
contact
Output
X1 X1
contact
Fig. 3-2 Internal connection diagram
⑤Output contact setting (MGR-A3V-R only)
It displays the setting condition of output contact
in accordance with the setting switch of SW2.
The setting is self-hold, the display shows
Ｈｏ..
The setting is auto-reset, the display shows
ＦＵ..
4. Fault record function
①Display of fault records
When a fault occurs, the relay outputs the
operating signal, and at the same time the input
value of zero-sequence current is recorded. When
the indicator select switch is set to the position
of fault record, the records are displayed starting
from the latest record to the oldest one at
approximately 2 second intervals. The relay can
save the newest five phenomena.
The records are saved in the non-volatile memory,
therefore the records can be read again after
shutting the power off.
Note that the fault record may not be saved if the
auxiliary power supply is turned off soon after
the relay operation.
②Clearing of fault records
Set indicator select switch to "CLEAR FAULT REC."
and hold for 5s or more, then Ｏ.Ｋ. is displayed
and all of the fault record are cleared.
5. Display function of setting change
When a setting is changed, the setting value after
changing is displayed for approx. 3s preferentially.
Z1
Level
I
0
assessment
Z2
c
b
P1
Auxiliary
a
power
Power supply
supply
P2
B1
B2
Continuous
monitoring
Power circuit
monitoring
E
10
Operation
indicator
RUN indicator
Output
X0
contact
Output
X1
contact
b）MGR-A3T-R
X0
T1
T2
O1
X0
X0
O2
S2
S1
L
SO
X1
B1
B2
E
JEP0-IL9555