GE LPS-D Instruction Manual page 318

13.2 DESIGN CONSIDERATIONS
Table 13–1: PICKUP DELAY TIMER TRUTH TABLE
S
L
13
↑
X
X
X
d) COUNTERS
The counter has two input line, one output line, and a user selected count threshold (in milliseconds) as shown
in Figure 13–5: COUNTER. A transition from low (binary 0) to high (binary 1) on the S input line increments the
counter by a value of one. The O output line is high (binary 1) when the accumulated count is equal to or
greater than the count threshold. If the O output line is low (binary 0), then the accumulated count is less than
the set value. A transition from low (binary 0) to high (binary 1) on the R input line resets the counter to zero.
13-
4
S
R
Figure 13–4: PICKUP DELAY TIMER
R Previous Timer State
L NOT TIMING
L NOT TIMING
L TIMING DOWN
H TIMING DOWN
↑
NOT TIMING
S
R
Figure 13–5: COUNTER
LPS-D Line Protection System
1000
S O
R O
Current Timer State
NOT TIMING
TIMING DOWN
TIMER EXPIRED
TIMER RESET
NOT TIMING
5
0 0 0 0
13 XPRESSION BUILDER
RO SO
RO L
n-1
L L
L H
H L
L L
O
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