4.4
SEL-2032 Communications Processor Instruction Manual Date Code 20120126
SELOGIC Control Equations
Equation Syntax
Equation Syntax
You create SELOGIC control equations by combining terms (inputs described
above) in logical equations. This section describes the syntax of these
equations. The simplest equation consists of directly entering a single
element. More complex equations require the use of logical operators.
Operators
You can create SELOGIC control equations that use multiple SEL-2032
elements with logical AND (*), OR (+), and inversion (!) operators in a single
equation. The following list defines the use of these operators.
Insert a backslash (\) symbol at the end of the line of a SEL
OGIC control
equation (just before pressing <Enter>) to continue the same equation on a
subsequent line. Otherwise, the equation may only be one line. There is a 200-
characters-per-equation limit for a single equation and a 50-term (element
names and time functions) limit per equation.
Operator
Precedence
When the SEL-2032 processes the SELOGIC control equations, the ! is applied
first, followed by AND (*) functions, and finally by OR (+) functions. The *,
+, and ! functions may be used in any combination. For example, consider the
equation:
Equation 4.1
This logic says that the AND function (*) is performed on assigned values for
intermediate elements X and Y, Z and V before they are ORed (+) to
determine the state of output 4 (OUT4=(X*Y)+(Z*V)). This is typically
referred to as a sum-of-products equation.
Equation
Disabling
Programming an equation to NA disables that function, i.e., OUT4 = NA.
Limitations
Table 4.1 lists unacceptable combinations of SELOGIC control equation
operators:
* AND Requires that elements on both sides of the * symbol be
asserted before the logic condition is true. For example, in
the equation OUT1=IN1*IN2 the terms IN1 and IN2 must
both be true for OUT1 to be true.
+ OR Requires that one element on either side of the + symbol be
asserted before the logical condition is true. The equation
OUT1=IN1+IN2 requires either IN1 or IN2 to be true for
OUT1 to be true.
! Invert Inverts the value of the element immediately following the !
symbol. For example, the equation OUT1=IN1*!IN2
requires IN1 to be true and IN2 to be false for OUT1 to be
true.
Tab l e 4 . 1 U na cc e p t ab l e S EL OGIC Control Equation Operator Combinations
*+ ** !* !+
+* ++ !!
Courtesy of NationalSwitchgear.com
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