6.20
SEL-311C Relay Instruction Manual Date Code 20060320
Close and Reclose Logic
Reclosing Relay
Settings Example
The drive-to-lockout example setting is:
79DTL = !IN102 + LB3 + OC
Optoisolated input IN102 is set to operate as a reclose enable switch (see
Optoisolated Inputs on page 7.3). When Relay Word bit IN102 = logical 1
(reclosing enabled), the relay is not driven to the Lockout State (assuming
local bit LB3 = logical 0, too):
!IN102 = !(logical 1) = NOT(logical 1) = logical 0
79DTL = !IN102 + LB3 + OC = (logical 0) + LB3 = LB3 + OC
When Relay Word bit IN102 = logical 0 (reclosing disabled), the relay is
driven to the Lockout State:
!IN102 = !(logical 0) = NOT(logical 0) = logical 1
79DTL = !IN102 + LB3 + OC = (logical 1) + LB3 + OC = logical 1
Local bit LB3 is set to operate as a manual trip switch (see Local Control
Switches on page 7.7 and Trip Logic on page 5.1). When Relay Word bit
LB3 = logical 0 (no manual trip), the relay is not driven to the Lockout State
(assuming optoisolated input IN102 = logical 1, too):
79DTL = !IN102 + LB3 + OC = NOT(IN102) + (logical 0) + OC =
NOT(IN102) + OC
When Relay Word bit LB3 = logical 1 (manual trip), the relay is driven to the
Lockout State:
79DTL = !IN102 + LB3 + OC = NOT(IN102) + (logical 1) + OC = logical 1
Relay Word bit OC asserts for execution of the OPE command.
The drive-to-last shot setting is:
79DLS = 79LO
Two open intervals are also set in the example 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 IN102 (reclose enable switch) is in the “disable
reclosing” position (Relay Word bit IN102 = 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).
Additional Settings Example 1
The preceding drive-to-lockout settings example drives the relay to the
Lockout State immediately when the reclose enable switch (optoisolated input
IN102) is put in the “reclosing disabled” position (Relay Word bit IN102 =
logical 0):
79DTL = !IN102 + ... = NOT(IN102) + ... = NOT(logical 0) + ... = logical 1
To disable reclosing, but not drive the relay to the Lockout State until the relay
trips, make settings similar to the following:
79DTL = !IN102 * TRIP + ...
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