4.16
SEL-587Z Instruction Manual
Date Code 20020903
Control Logic
Trip Logic (TRn, ULTRn, TDURD)
Trip Logic (TRn, ULTRn, TDURD)
The trip logic in
provides flexible tripping with the following three
SEL
OGIC
control equation settings:
TR
n
–Trip Conditions
ULTR
n
–Unlatch Trip Conditions
TDURD–Minimum Trip Duration Time
Figure 4.7
Trip Logic.
Set Trip
Any time setting TR
n
= logical 1, Relay Word bit TRIP
n
asserts to logical 1,
regardless of other trip logic conditions.
As shown in the time line example in
, the Minimum Trip Duration
Timer (setting TDURD) outputs a logical 1 for a time duration of “TDURD”
cycles any time it sees a rising edge on its input (logical 0 to logical 1
transition), if it is not already timing. The TDURD timer assures that the TRIP
Relay Word bit remains asserted at logical 1 for a minimum of “TDURD”
cycles. If SEL
OGIC
control equation setting TR
n
= logical 1 beyond the
TDURD time, Relay Word bit TRIPn remains asserted at logical 1 for as long
as TR
n
= logical 1. In this case, when TR
n
finally deasserts (TR
n
= logical 0),
the TRIP
n
Relay Word bit deasserts immediately, i.e., the TDURD time is not
considered again.
Unlatch Trip
Once Relay Word bit TRIP
n
is asserted to logical 1, it remains asserted at
logical 1 until both of these conditions are true:
Trip Duration Timer stops timing (output of the TDURD timer
goes to logical 0).
SEL
OGIC
control equation setting TR
n
deasserts to logical 0.
Example operation
of SEL
OGIC
control
equation setting TRn
(input into Minimum Trip
Duration Timer and OR–1)
Resultant logic
output of Minimum Trip
Duration Timer (input into OR–1)
Rising-edge
input occurring
when the Minimum
Trip Duration Timer is reset
OR–combination of above
two logic traces (inputs into
OR–1 to drive Relay Word bit TRIPn)
0
TDURD
Minimum Trip
Duration Timer
rising-edge detect
TRIPn
Relay
Word
Bit
OR
1
(out)
(in)
ULTRn
TDURD
TDURD
TDURD
TARGET RESET
Pushbutton
TAR R
Serial Port Command
TRn
Setting
Содержание SEL-587Z
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