Schweitzer Engineering Laboratories SEL-587Z - SELOGIC Control Equations; Logical Operators

4.11
Date Code 20020903 SEL-587Z Instruction Manual
Control Logic
SEL
OGIC Control Equations
SELOGIC Control Equations
The outputs of the logic in most of the figures in this section are Relay Word
bits. Relay Word bits have label names (e.g., 87A1, TRIP, CLOSE, etc.).
These are logic points that can have a state of logical 1 or logical 0 depending
on the operation of the associated logic. Logical 1 represents an element being
picked up, timed out, or otherwise asserted. Logical 0 represents an element
being dropped out or otherwise deasserted. All Relay Word bits and
descriptions are shown in the tables that appear in Appendix C: Relay Word
Bits.
In addition to Relay Word bits, numerals 1 (logical 1) or 0 (logical 0) can be
entered in a SEL
OGIC control equation setting. If a SELOGIC control equation
setting is set equal to 1, it is always “asserted/on/enabled.” If a SEL
OGIC
control equation setting is set equal to 0, it is always “deasserted/off/disabled.”
Under SHO (Showset) on page 7.15 in Section 7: ASCII Command Reference,
note that a number of the factory SEL
OGIC control equation settings are set
equal to 1 or 0.
SEL
OGIC control equation settings are the inputs for the logic in many of the
figures in this section. See the SEL-587Z Settings Sheets in Section 5: Setting
the Relay for a listing and short description of each of the SEL
OGIC control
equation settings. See SHO (Showset) on page 7.15 in Section 7: ASCII
Command Reference for a listing of the factory SEL
OGIC control equation
settings shipped with the relay.
Logical Operators
SELOGIC control equation settings are written in Boolean algebraic logic,
combining Relay Word bits together with different operators. Parentheses can
also be used in SEL
OGIC control equation settings. More than one set of
parentheses can be used in a given SEL
OGIC control equation setting, but they
cannot be “nested” (parentheses within parentheses). Operators in a SEL
OGIC
control equation setting are processed in the order indicated in Table 4.5.
The *, +, and ! functions may be used in any combination for any output
contact.
The relay will not accept the following order of SEL
OGIC control equation
operators: *+, **, +*, ++, !*, !+, !!, ( ).
Programming SEL
OGIC control equations consists of combining relay element
bits with logic AND (*), OR (+), inversion (!), and single parentheses () in a
single string for each SEL
OGIC control equation variable. Table 4.6 on
page 4.12 defines the use of these operators and important logic elements.
Table 4.5 Processing Order of SELOGIC Control Equation Operators
Operator Logic Function
( ) parentheses
!NOT
* AND
+OR