Schweitzer Engineering Laboratories SEL-587Z - Table 4.6 SEL OGIC Control Equation Logic

4.12
SEL-587Z Instruction Manual Date Code 20020903
Control Logic
SEL
OGIC Control Equations
Application Rules
Number of Elements
Any single SELOGIC control equation setting is limited to nine Relay Word
bits that can be combined with the SEL
OGIC control equation operators listed
in Table 4.5 on page 4.11. To get around this limitation, a SEL
OGIC control
equation variable (SEL
OGIC control equation settings SV1 through SV14) can
be used as an intermediate setting step (see SEL
OGIC Control Equation
Variables/Timers on page 4.14).
For example, presume that the trip equation (SEL
OGIC control equation setting
TR1) needs more than nine Relay Word bits in its equation setting. Part of the
desired equation is put into the SEL
OGIC control equation setting SV1. The
resultant SEL
OGIC control equation variable output (Relay Word bit SV1) is
then set in SEL
OGIC control equation setting TR1.
Note in Table 4.7 on page 4.13 that the SEL
OGIC control equation variables
(SEL
OGIC control equation settings SV1 through SV14) are processed after
the trip equation (SEL
OGIC control equations setting TR). Thus, any tripping
via Relay Word bit SV1 is delayed one processing interval (1/8-cycle). For
most applications, this is probably of no consequence.
As many as 250 Relay Word bits can be used to create SEL
OGIC control
equation settings. You can build the equations using Relay Word bits in
combination with the SEL
OGIC control equation operators listed in Tabl e 4 .5
on page 4.11.
Ta b le 4. 6 S E LOGIC Control Equation Logic
Logic Definition
* Logical AND. This symbol requires that the
elements on either side of the * symbol be asserted
before the logic condition is true, for example 51P * 50P1 = OUT1.
+ Logical OR. This symbol requires that only one element on
either side of the + symbol be asserted before the logical condition is true.
! Invert. This symbol inverts the element immediately following the ! symbol.
\ At the end of the first line of a SEL
OGIC control equation, just
before the [RETURN], the \ continues the same equation to the second line.
( ) Parentheses group variables together and tell the
relay to process the variables within the parentheses first.
0 Set equation to logical zero.
NA Set equation to logical zero. Null (blank or do not run) an equation or label.
1 Set equation to logical one.