RJS Inspector D4000 Auto Optic (FIRMWARE version A.05 and Earlier) - Manual (Page 62)

Operator
’
s Guide Appendix J
002-5564 RJS, Minneapolis, MN 55
The overall symbol grade is averaged for the Reference Decode parameter:
For example, if 2 scans are averaged and one passes reference decode and the other fails
reference decode, (assuming all other parameters scan “A” or “B”), the average would be a
“C” (the average of “A” and “F”).
The average grade for the reference decode parameter would be “F” however as a warning
that at least one scan failed this parameter.
Decodability
This parameter grade can be “A,” “B,” “C,” “D,” or “F.”
The decodability grade indicates the amount of error in the width of the most deviant element
in the symbol. The lower the deviation, the higher the grade.
Each symbology type has a specified method for calculating decodability but the basic idea is
the same for all.
Each element size in a bar-code symbol should be consistent across the symbol. In the case
of Code 39 there are 2 element widths needed to produce a symbol.
For optimum scanning, each narrow element (bar or space) should be the same dimension,
and each wide element (bar or space) should be the same dimension.
Symbol Contrast
This parameter can also be “A,” “B,” “C,” “D,” or “F.”
Symbol contrast is the difference in reflectance values of the “lightest” space (including the
quiet zone) and the “darkest” bar of the symbol. The greater the difference, the higher the
grade.