Rockwell Automation 2755 2D Hand-Held Scanner - Manual (Page 110)

E–12 Advanced Data Formatting
Publication 2755-6.4
Rules Hierarchy (in Bar Codes)
In addition to the correct programming of rules, you must be aware
of the order of programming individual rules. Program the most
general rule last.
All programmed rules are stored in a buffer. As they are
programmed, they are stored at the top of a rules list. If three rules
have been created, the list would be configured as follows:
•
Third Rule
•
Second Rule
•
First Rule
When data is scanned, the rules list is checked from top to bottom to
determine if the criteria matches (and the actions should occur).
Input is modified into the data format specified by the first matching
set of criteria it finds.
Important: The order of rules in the buffer is very important. Be
sure that your most general rule is the last one programmed.
For example, if the Third Rule states:
When scanning a bar code of any length, send all data, then
send the ENTER key.
And the Second Rule states:
When scanning a 128 bar code of length 12, send the first four
characters, then send the ENTER key, then send remaining
data.
If a code 128 bar code of length 12 were scanned, the Third rule
would be in affect. The Second rule would appear not to function.
Note also that ADF rules are actually created when you use the
standard data editing functions. Scan options are entered as ADF
rules, and the hierarchy mentioned above also applies to them. For
the LS 4800 scanner, this applies to prefix/suffix programming when
selecting the Data Transmission Format.