5-6 Trip and Target Logic Date Code 20001006
SEL-351 Instruction Manual
• Relay Word bit OC asserts for execution of the OPEN Command. See OPE Command
(Open Breaker) in Section 10: Serial Port Communications and Commands for more
information on the OPEN Command.
With setting TDURD = 9.000 cycles, once the TRIP Relay Word bit asserts via SELOGIC Control
Equation setting TR, it remains asserted at logical 1 for a minimum of 9 cycles.
Unlatch Trip
In SELOGIC Control Equation setting ULTR = !(51P + 51G):
Both time-overcurrent element pickups 51P and 51G must be deasserted before the trip logic
unlatches and the TRIP Relay Word bit deasserts to logical 0.
ULTR = !(51P + 51G) = NOT(51P + 51G) = NOT(51P) * NOT(51G)
Additional Settings Examples
The factory setting for SELOGIC Control Equation setting ULTR is a current-based trip unlatch
condition. A circuit breaker status unlatch trip condition can be programmed as shown in the
following examples.
Unlatch Trip with 52a Circuit Breaker Auxiliary Contact
A 52a circuit breaker auxiliary contact is wired to optoisolated input IN1.
52A = IN1 (SELOGIC Control Equation circuit breaker status setting – see
Optoisolated Inputs in Section 7: Inputs, Outputs, Timers, and
Other Control Logic )
ULTR = !IN1
Input IN1 has to be deenergized (52a circuit breaker auxiliary contact has to be open) before the
trip logic unlatches and the TRIP Relay Word bit deasserts to logical 0.
ULTR = !IN1 = NOT(IN1)
Unlatch Trip With 52b Circuit Breaker Auxiliary Contact
A 52b circuit breaker auxiliary contact is wired to optoisolated input IN1.
52A = !IN1 (SELOGIC Control Equation circuit breaker status setting - see
Optoisolated Inputs in Section 7: Inputs, Outputs, Timers, and
Other Control Logic )
ULTR = IN1
Input IN1 must be energized (52b circuit breaker auxiliary contact has to be closed) before the trip
logic unlatches and the TRIP Relay Word bit deasserts to logical 0.
Courtesy of NationalSwitchgear.com
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