Publication 1747-RM001G-EN-P - November 2008
E-12 Data File Organization and Addressing
SLC 5/03 (OS301 and higher) SLC 5/04, and SLC 5/05 processors: When an
indexed string data file is specified, indexed addressing is not allowed to cross
a string element boundary. A run-time error will occur if you use an offset
value that results in crossing a string element boundary.
Example
The figure below indicates the maximum offset for word address #T4:3.ACC
when allowing and disallowing crossing file boundaries.
Crossing file boundaries disallowed: In the example above, the highest
numbered element in the timer data file is T4:9. This means that #T4:3.ACC
can have a maximum negative offset of -3 and a maximum positive offset of 6.
Crossing file boundaries allowed: The maximum negative offset extends to
the beginning of data file 3. The maximum positive offset extends to the end
of the highest numbered file created.
TIP
If a file is constant protected, indexing across file
boundaries is not allowed.
T4:0.ACC Maximum
negative of 3
B3:0
#T4:3.ACC
#T4:3.ACC
T4:9.ACC Maximum
positive of 6
End of highest
file created
Crossing file boundaries disallowed
Crossing file boundaries allowed
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