Parameter
Range
Default
Notes
Enabled
: Whenever the controller breaker trips, then the controller also
activates the
Non-essential load trip #
output. The NEL trip remains active as
long as the breaker trip is active.
The parameters for each alarm are given in the following sections.
How the NEL function works
Table 4.19
Sequence diagram example with NEL 1 over-current, without a latch
NEL 1
over-
current
NEL trip
NEL
breaker
(2)
(3)
(4)
Operator
(5)
Current
(1)
Delay
1.
Current
: The current fluctuates based on the demand.
When the current exceeds the set point, the alarm's delay
timer starts. If the current is over the set point for the delay
time, the alarm is activated and the NEL breaker trips. In
response, the current drops.
2.
NEL 1 over-current
: The controller activates the NEL
alarm when the operating value is above the set point for
the delay time.
•
The alarm is deactivated when the alarm value returns
to normal.
3.
NEL trip
:
Non-essential load trip > Non-essential load trip
#
(digital output): The controller activates this output when
an NEL alarm is activated. The output is deactivated when
all the NEL alarm values return to normal.
4.
NEL breaker
: The NEL breaker disconnects the NEL
when the controller activates the NEL trip output. The
operator has to close the breaker to reconnect the NEL.
5.
Operator
: Operator intervention is required to reconnect
the NEL.
Table 4.20
Sequence diagram example with NEL 1 over-current with a latch
NEL 1
over-
current
NEL trip
NEL
breaker
(2)
(3)
(4)
Operator
(5)
Current
(1)
Delay
1.
Current
: See the previous example.
2.
NEL 1 over-current
: The controller activates the NEL
alarm when the operating value is above the set point for
the delay time.
•
The alarm is reset when the latch is reset.
3.
NEL trip
:
Non-essential load trip > Non-essential load trip
#
(digital output): The controller activates this output when
an NEL alarm is activated. The output is deactivated when
all the NEL alarm values are normal, and all latches are
reset.
4.
NEL breaker
: The NEL breaker disconnects the NEL
when the controller activates the NEL trip output. The
operator has to close the breaker to reconnect the NEL.
5.
Operator
: Operator intervention is required to reset the
latch and reconnect the NEL.
DESIGNER'S HANDBOOK 4189340911K UK
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