Omron CX-PROGRAMMER 5.0-FUNCTION BLOCK OPERATION Operation Manual page 55

Restrictions on Function Blocks
ST Programming
Restrictions
Program Structure Precautions
No Branches to the Left of
the Instance
Only One Instance per
Rung
40
P _ On
FB1
EN ENO
0.00 a U P
• If the same instance containing a timer is used in multiple locations at the
same time, the timer will be duplicated.
• Only the following statements and operators are supported.
• Assignment statements
• Selection statements (CASE and IF statements)
• Iteration statements (FOR, WHILE, REPEAT, and EXIT statements)
• RETURN statements
• Arithmetic operators
• Logical operators
• Comparison operators
• Numerical Functions
• Arithmetic Functions
• Comments
• The TIMER and COUNTER data types cannot be used.
For further details, refer to Appendix B Structured Text (ST Language) Specifi-
cations.
Branches are not allowed on the left side of the instance. Branches are
allowed on the right side.
Incorrect
FB
Instruction
A program rung cannot have more than one instance.
Incorrect
FB
FB
Body
LD a
TI M t i m U P
The timer's completion flag (UP) is turned
OFF when input condition a (0.00) goes OFF.
Correct
FB
Instruction
Incorrect
FB
Section 2-3