13.7
Date Code 20171006 Instruction Manual SEL-400 Series Relays
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Programming
equations. You can also enter entire line comments to help document program-
ming. Mathematical operations are available only in freeform SEL
OGIC control
equation programming areas. An example of freeform SEL
OGIC control equation
programming is shown in Example 13.2.
Assignment Statements
Both fixed and freeform SELOGIC control equations are a basic type of computer
programming statement called an assignment statement. Assignment statements
have a basic structure similar to that shown below:
LVALUE := Expression
Starting at the left, the LVALUE is the location where the result of an evaluation
of the expression on the right will be stored. The := symbol marks the statement
as an assignment statement and provides a delimiter or separator between the
LVALUE and the expression. Type the := symbol as a colon and equal sign. The
assignment symbol is different than a single equal sign (=) to avoid confusion
with a logical comparison between two values. The type of LVALUE must match
the result of evaluating the expression on the right.
There are two basic types of assignment statements that form SEL
OGIC control
equations. In the first type, Boolean SEL
OGIC control equations, the relay evalu-
ates the expression on the right to a result that is a logical 1 or a logical 0. The
LVALUE must be some type of Boolean storage location or setting that requires a
Boolean value. For example, the setting for the Protection Conditioning Timer 7
Input, PCT07IN, requires a value of 0 or 1, which you set with a Boolean
SEL
OGIC control equation.
The second type is a math SEL
OGIC control equation. Use the math SELOGIC
control equation to perform numerical calculations on data in the relay. For
example, in protection freeform programming in an SEL-451, enter
AMV034 := 5 * BK1IAFM to store the product of 5 and the Circuit Breaker 1
A-Phase current in automation math variable 34. Example 13.3 lists several
examples of Boolean and math SEL
OGIC control equations.
Example 13.2 Freeform SELOGIC Control Equations
The following equations are examples of freeform SELOGIC control equa-
tions. The text after the # character is a comment included in the equation
and stored in the relay for future reference and documentation.
# Freeform equation example programming
#
# Is 80% of A-Phase fundamental voltage greater than 12kV?
PMV01 := VA F M * 0 . 8 # 80% of A-Phase fundamental voltage
PSV04 := PMV01 >= 12000 # True if A-Phase fundamental voltage
is greater than or equal to 12000
Use comments to group settings in the freeform SEL
OGIC control equations
by task and to document individual equations. In this example, an intermedi-
ate calculation generates the value we want to test to determine if PSV04
will be turned on.
To Next Page
Loading...
