Parker Hannifin
When using an
IF/THEN
statement, observe the following:
•
You can nest
GOTO
and
GOSUB
statements in an
IF/THEN
statement.
Example
The following demonstrates several simple
IF/THEN
statements.
IF (BIT 24) THEN P0 = P0+1
IF (P0 > 4000) THEN GOSUB 100 : P0 = P0-1
IF/ELSE
The
IF/ELSE
statement provides a powerful tool for program
branching and program flow control. The
IF/ELSE
statement allows
you to run one set of code if the condition is true, and another set of
code if the condition is false. The
IF/ELSE
statement must end with
ENDIF
.
When using an
IF/ELSE
statement, observe the following:
•
You can nest
GOSUB
statements in an
IF/ELSE
statement. The
GOSUB
provides a return into the
IF/ELSE
statement.
•
Do not nest
GOTO
statements in
IF/ELSE
statements. The
GOTO
statement exits the
IF/ELSE
statements, and does not provide
any link back inside.
•
Do not nest
IF/THEN
statements in
IF/ELSE
statements—the logic
may not provide the results you expect.
Tip:
When troubleshooting programs, use the
LIST
command to
view the program stored on the controller. In recognizing
IF/ELSE
statements, the controller indents the statements
under the
IF
including the
ENDIF
. If any statements in the
IF/ELSE
are not indented but should be, check the code in
the program editor and re-download.
Example
The following demonstrates different actions based on conditions
being true or false. If the input (bit 24) is true, the long array
increments and axis X moves an incremental 25 units. If false, the
long array decrements and axis Y moves to absolute position 5.
IF (BIT 24)
LA0(1) = LA0(1)+1
X/25
ELSE
LA0(1) = LA0(1)-1
Y5
ENDIF
20 Programmer’s Guide
