Rockwell Automation 5370-OCR2 PAK - Manual (Page 64)

Chapter 6
Using Match Strings
6–2
Length of Match Strings
Although each string of an OCR Tool can only read up to 20 characters, its
match string may be up to 80 characters long. This allows for relatively
complex matching capability using metacharacters.
Leading & Trailing Spaces
If there is sufficient room within the OCR Tool’s processing window, the tool
will check for spaces in the regions immediately before and after each string,
and will add either a white space or gray space to the beginning and end of
the read text. If the characters which correlate are too close to the left and/or
right edges of the processing window, then no white or gray space will be
added to the beginning and/or end of the read text. See page 2–6
In some applications, an inspected character string would be acceptable
whether or not there was sufficient room to check for spaces before and after
the string. In this case, the match string should begin and end with the
sequence
h? to indicate that a space is optional.