Date Code 20001006 Setting SELOGIC
®
Control Equations G-9
SEL-351 Instruction Manual
With SH0 = 0 and 50P1 = 1, the ANDed combination results in:
50P1*SH0 = 1*0 = 0 (logical 0)
and no trip results from phase instantaneous overcurrent element 50P1.
A trip will eventually result if time-overcurrent element 51PT or 51GT times out. If residual
ground time-overcurrent element 51GT times out, Relay Word bit 51GT is in the following state:
51GT = 1 (logical 1)
When shot = 1, SH0 = 0 and the result is:
TR = 51PT+51GT+50P1*SH0 = 0 + 1 + 1*0 = 0 + 1 + 0 = 1
and a time-delayed trip results from residual ground time-overcurrent element 51GT.
Set an Output Contact for Tripping
To assert output contact OUT1 to trip a circuit breaker, make the following SELOGIC Control
Equation output contact setting (see Output Contacts in Section 7: Inputs, Outputs, Timers, and
Other Control Logic):
OUT1 = TRIP
All SELOGIC Control Equations Must Be Set
All SELOGIC Control Equations must be set one of the following ways (they cannot be “blank”):
• single Relay Word bit (e.g., 52A = IN1)
• combination of Relay Word bits (e.g., TR = 51PT+51GT+50P1*SH0)
• directly to logical 1 (e.g., 67P1TC = 1)
• directly to logical 0 (e.g., TRCOMM = 0)
Set SELOGIC Control Equations Directly to 1 or 0
SELOGIC Control Equations can be set directly to:
1 (logical 1) or 0 (logical 0)
instead of with Relay Word bits. If a SELOGIC Control Equation setting is set directly to 1, it is
always “asserted/on/enabled.” If a SELOGIC Control Equation setting is set equal to 0, it is always
“deasserted/off/disabled.”
Note: SELOGIC Control Equation torque control settings (e.g., 67P1TC, 51P1TC) cannot be set
directly to logical 0.
Under the SHO Command (Show/View Settings) in Section 10: Serial Port Communications
and Commands, note that a number of the factory SELOGIC Control Equation settings are set
directly to 1 or 0.
Courtesy of NationalSwitchgear.com
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