A trip logic equation consists of logic variables joined by logic and timer operators in following syntax.:
[(] [!] Var [*|+ [!]Var]|[@|^|~ Const][)]…
Note: Tokens inside square brackets [] are optional. |-delimited list shows valid tokens that can be used at the given position. The pattern shown above can be repeated indefinitely to form a complete equation.
Where:
Var Logic variable
name
Const Timer constant
name.
! Logic operator
NOT
*
Logic operator AND
+ Logic operator
OR
@
Transmission delay operator
^ Pickup timer
operator
~
Dropout timer operator
(
) Pair of parentheses that forms single equation
term
Equation variables and constants must have a unique name that consists of only alpha numeric characters or underscore. First character in a name must be a letter. All operators in the logic equation have the same priority and equations are parsed from left to right. In order to modify the order in which expressions are evaluated, place them inside of the parenthesis.
An example equation for the directional blocking is:
!(REV_FAR ~ Tr @ Ts) * (RO_NEAR ^ Tc)
In this equation REV_FAR and RO_NEAR are variables, and Tr, Tc and Ts are time-delay constants.