ABB ACSM1 Series, Руководство пользователя

Страница: 398 / 510

Standard function blocks
398
IF
(10103)
Illustration
Execution time -
Operation The IF, ELSE, ELSEIF and ENDIF blocks define, by Boolean logic, which parts of the
application program are executed.
If the condition input (COND) is true, the blocks between the IF block and the next
ELSEIF, ELSE or ENDIF block (in execution order) are run. If the condition input
(COND) is false, the blocks between the IF block and the next ELSEIF, ELSE or ENDIF
block are skipped.
The outputs of the “branches” are collected and selected by using the
BOP block.
Example:
Bit 4 of
2.01 DI STATUS (digital input DI5) controls the branching of the application
program. If the input is 0, the blocks between the IF and ELSE blocks are skipped but
the blocks between ELSE and ENDIF are run. If the input is 1, the blocks between IF
and ELSE are run. The program execution then jumps to the block that follows ENDIF,
which is a BOP. The BOP block outputs the value from the branch that was executed. If
the digital input is 0, the BOP block output is 2; if the digital input is 1, the BOP block
output is 1.
Inputs Input (COND): Boolean
Outputs -