TD_MRN3-3_08.06_GB
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5.4.10 Voltage threshold value for
frequency and vector surge
measuring
(df/dt)
Correct frequency measuring or vector surge measur-
ing cannot be obtained if the system voltage is very
low, for instance during generator start up or voltage
failure. False tripping of the
MRN3-3
in such cases is
prevented by an adjustable voltage threshold U
B
. If the
system voltage is below this threshold, these functions
of the relay are blocked.
During adjustment of U
B
< LEDs f and
∆Θ
or df light up
in the upper display part.
5.4.11 Adjustment of the slave address
By pressing push buttons <+> and <-> the slave ad-
dress can be set in the range of 1 - 32. During this ad-
justment the LED RS lights up in the upper display part.
5.4.12 Setting of Baud-rate (applies for
Modbus Protocol only)
Different transmission rates (Baud rate) can be set for
data transmission via Modbus Protocol.
The rate can be changed by push buttons <+> and
<-> and saved by pressing <ENTER>.
5.4.13 Setting of parity (applies for
Modbus Protocol only)
The following three parity settings are possible :
•
"even" =
even
•
"odd" =
odd
•
"no"
= no parity check
The setting can be changed by push buttons <+> and
<-> and saved by pressing <ENTER>.
5.5 Adjustment of the fault recorder
The
MRN3-3
is equipped with a fault recorder (see
chapter 3.1.5). Three parameters can be determined.
5.5.1 Number of the fault recordings
The max. recording time is 20 s at 50 Hz or 16.66 s
at 60 Hz.
The number of max. recordings requested has to be
determined in advance. There is a choice of 1, 2, 3,
4, 7 or 8 recordings and dependent on this the dura-
tion of the individual fault recordings is defined, i.e.
1 recording for a duration of 20 s (with 50 Hz)
(16.66 s with 60 Hz)
1*/2 recordings for a duration of 10s (with 50 Hz)
(8.33s with 60 Hz)
3*/4 recordings for a duration of 5 s (with 50 Hz)
(4.16 s with 60 Hz)
7*/8 recordings for a duration of 2.5 s (with 50 Hz)
(2,08 s with 60 Hz)
* is written over when a new trigger signal arrives
If the respective partition was defined as not being
overwriteable and the maximal number of recorded
disturbance events was assigned, the LED FR starts
flashing (refer to chapters 3.1.5 and 5.9.3).
Caution:
If the fault recorder is used, the frequency should be
set to f = 50 Hz or f = 60 Hz (see chapter 5.3.3).
5.5.2 Adjustment of trigger occurences
There is a choice between four different occurrences:
P_UP (PickUP)
Storage is initiated after recognition
of a general activation.
TRIP
Storage is initiated after a trip has
occurred.
A_PI (After Pickup) Storage is initiated after the last
activation threshold was fallen
short of.
TEST
Storing is immediately activated by
simultaneous actuation of the keys
<+> and <->. During the recording
time the display shows “Test”.
