5-26 Trip and Target Logic Date Code 20001006
SEL-351 Instruction Manual
DSTRT – Directional Carrier Start
Program an output contact for directional carrier start. For example, SELOGIC Control Equation
setting OUT5 is set:
OUT5 = DSTRT
Output contact OUT5 drives a communications equipment transmitter input in a two-terminal line
application (see Figure 5.15).
In a three-terminal line scheme, output contact OUT7 is set the same as OUT5 (see Figure 5.16):
OUT7 = DSTRT
DSTART includes current reversal guard logic.
NSTRT – Nondirectional Carrier Start
Program an output contact to include nondirectional carrier start, in addition to directional start.
For example, SELOGIC Control Equation setting OUT5 is set:
OUT5 = DSTRT + NSTRT
Output contact OUT5 drives a communications equipment transmitter input in a two-terminal line
application (see Figure 5.15).
In a three-terminal line scheme, output contact OUT7 is set the same as OUT5 (see Figure 5.16):
OUT7 = DSTRT + NSTRT
STOP – Stop Carrier
Program to an output contact to stop carrier. For example, SELOGIC Control Equation setting
OUT6 is set:
OUT6 = STOP
Output contact OUT6 drives a communications equipment transmitter input in a two-terminal line
application (see Figure 5.15).
In a three-terminal line scheme, output contact OUT8 is set the same as OUT6 (see Figure 5.16):
OUT8 = STOP
BTX – Block Trip Extension
The received block trip input (e.g., BT = IN4) is routed through a dropout timer (BTXD) in the
DCB logic in Figure 5.14. The timer output (BTX) is routed to the trip logic in Figure 5.1.
Courtesy of NationalSwitchgear.com
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