Date Code 20001006 Close and Reclose Logic 6-23
SEL-351 Instruction Manual
Factory Settings Example
The drive-to-lockout factory setting is:
79DTL = OC + !IN2 + LB3
Optoisolated input IN2 is set to operate as a reclose enable switch (see Optoisolated Inputs in
Section 7: Inputs, Outputs, Timers, and Other Control Logic). When Relay Word bit
IN2 = logical 1 (reclosing enabled), the relay is not driven to the Lockout State (assuming local bit
LB3 = logical 0, too):
!IN2 = !(logical 1) = NOT(logical 1) = logical 0
79DTL = OC + !IN2 + LB3 = OC + (logical 0) + LB3 = OC + LB3
When Relay Word bit IN2 = logical 0 (reclosing disabled), the relay is driven to the Lockout State:
!IN2 = !(logical 0) = NOT(logical 0) = logical 1
79DTL = OC + !IN2 + LB3 = OC + (logical 1) + LB3 = logical 1
Local bit LB3 is set to operate as a manual trip switch (see Local Control Switches in Section 7:
Inputs, Outputs, Timers, and Other Control Logic and Trip Logic in Section 5: Trip and
Target Logic). When Relay Word bit LB3 = logical 0 (no manual trip), the relay is not driven to
the Lockout State (assuming optoisolated input IN2 = logical 1, too):
79DTL = OC + !IN2 + LB3 = OC + NOT(IN2) + (logical 0) = OC + NOT(IN2)
When Relay Word bit LB3 = logical 1 (manual trip), the relay is driven to the Lockout State:
79DTL = OC + !IN2 + LB3 = OC + NOT(IN2) + (logical 1) = logical 1
Relay Word bit OC asserts for execution of the OPEN Command. See the Note in the Lockout
State discussion, following Table 6.1.
The drive-to-last shot factory setting is:
79DLS = 79LO
Two open intervals are also set in the factory settings, resulting in last shot = 2. Any time the relay
is in the lockout state (Relay Word bit 79LO = logical 1), the relay is driven to last shot (if the shot
counter is not already at a shot value greater than or equal to shot = 2):
79DLS = 79LO = logical 1
Thus, if optoisolated input IN2 (reclose enable switch) is in the “disable reclosing” position (Relay
Word bit IN2 = logical 0) or local bit LB3 (manual trip switch) is operated, then the relay is driven
to the Lockout State (by setting 79DTL) and, subsequently, last shot (by setting 79DLS).
Courtesy of NationalSwitchgear.com
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