Figure 2.2: Programmable Trip Logic Diagram - Schweitzer Engineering Laboratories SEL-267D Instruction Manual

The Programmable Trip Logic is shown in Figure 2.2.

Figure 2.2: Programmable Trip Logic Diagram

The general form for each output equation follows:
Let R = Relay Word
M T U = mask for trip (unconditional)
M P T = mask for trip (permissive trip)
M T B = mask for trip (with no blocking)
M T O = mask for trip (with breaker open)
Then: TRIP = R * MTU
close TRIP contact
open TRIP contact
close CLOSE contact =
open CLOSE contact
Al = R * MA1
A2 = R * MA2
A3 = R * MA3
A4 = R * MA4
The "*" symbol indicates logical " and", while the "+" indicates logical "or".
2-16
THIS LOGIC REPEATS FOR EACH BIT IN RELAY WORD
+ R * MPT * PT
+ R * MTB * NOT (BT)
+ R * MTO * 52BT
=
TRIP
= NOT (TRIP) * [NOT(Any element in Relay Word Row 1 picked
up) + (TARGET RESET button pushed] * Trip Duration timer
expired (TDUR)]
(DC + 79OI1 + 79OI2 + 79OI3 + CLOSE command) * NOT
(52A)
= NOT (CLOSE) + 79RS
Specifications
SEL-267D/167D Instruction Manual
Date Code 920326