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Checking Programs Section 2-3
Note Output duplication is not checked between tasks, only within individual tasks.
Operand ranges Operand area ranges
Operand data types
Access check for read-only words
Operand range checks, including the following.
• Constants (#, &, +, –)
• Control codes
• Area boundary checks for multi-word operands
• Size relationship checks for multi-word operands
• Operand range overlaps
• Multi-word allocations
• Double-length operands
• Area boundary checks for offsets
Program capacity
for PLC
Number of steps
Overall capacity
Number of tasks
Syntax Call check for paired instructions
•IL–ILC
• JMP–JME, CJP/CJPN-JME
• SBS–SBN–RET, MCRO–SBN–RET
• STEP–SNXT
• BPRG–BEND
•IF–IEND
• LOOP–LEND
Restricted programming locations for BPRG–BEND
Restricted programming locations for SBN–RET
Restricted programming locations for STEP–SNXT
Restricted programming locations for FOR–NEXT
Restricted programming locations for interrupt tasks
Required programming locations for BPRG–BEND
Required programming locations for FOR–NEXT
Illegal nesting
END(001) instruction
Number consistency
Ladder diagram
structure
Stack overflows
Output duplication Duplicate output check
•By bit
•By word
• Timer/counter instructions
• Long words (2-word and 4-word)
• Multiple allocated words
• Start/end ranges
• FAL numbers
• Instructions with multiple output operands
Tasks Check for tasks set for starting at beginning of operation
Task program allocation
Area Check
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