480 D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
AUTOMATION LOGIC CHAPTER 8: AUTOMATION
Figure 410: Using comparators to verify approximate equivalence
Automation timers
Unlike earlier versions of the D90
Plus
, automation timers are implemented like gates or
latches and not through setting menus. Automation timers have the following syntax:
TIMER (IN, PKP, DPO).
A timer accepts any digital input or the output of any logical operator as its IN parameter.
The timer output asserts when its input is asserted for a time equal to or greater than the
PKP parameter. Likewise, the timer output resets when its input has been reset for a time
equal to or greater than its DPO parameter.
For example, the following logic produces an output that picks up 10 seconds after contact
input F1 closes and drops out one second after the contact opens.
Figure 411: Using an automation timer
Virtual analogs also can be assigned to control the pickup and dropout of timers. In the
following example, two virtual analogs are used to define the pickup and dropout of two
timers.
$&'5
65&,$506
65&,$506
68%D²E
D
E
68%
$%6
$%6
²
/(667+$1
$8792$92
$8792$92
%.5$21)
$7,0(5
$8792$92
$7,0(5
$&'5
$8792$9
,1
3.
'3
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