Yaskawa SMC–4000 - Manual (Page 325)

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SMC–4000 User Manual
If, Else, and Endif
The SMC–4000 provides a structured approach to conditional statements using IF, ELSE and ENDIF
commands.
Using the IF and ENDIF Commands
An IF conditional statement is formed by the combination of an IF and ENDIF command. The IF
command has as it's arguments one or more conditional statements. If the conditional statement(s)
evaluates true, the command interpreter will continue executing commands which follow the IF
command. If the conditional statement evaluates false, the controller will ignore commands until the
associated ENDIF command is executed OR an ELSE command occurs in the program (see discussion of
ELSE command below).
NOTE:An ENDIF command must always be executed for every IF command that has been executed. It
is recommended that the user not include jump commands inside IF conditional statements since
this causes re-direction of command execution. In this case, the command interpreter may not
execute an ENDIF command.
NOTE:Do not jump (JP) out of an IF block. If this occurs, the ENDIF instruction will never be executed.
Using the ELSE Command
The ELSE command is an optional part of an IF conditional statement and allows for the execution of
command only when the argument of the IF command evaluates False. The ELSE command must occur
after an IF command and has no arguments. If the argument of the IF command evaluates false, the
controller will skip commands until the ELSE command. If the argument for the IF command evaluates
true, the controller will execute the commands between the IF and ELSE command.
Nesting IF Conditional Statements
The SMC–4000 allows IF conditional statements to be included within other IF conditional statements.
This technique is known as 'nesting' and the SMC–4000 allows up to 255 IF conditional statements to be
nested. This is a very powerful technique allowing the user to specify a variety of different cases for
branching.