Section 3: Configuring a Wafer ID Application In-Sight
®
1700 Series Wafer Reader
26
SELECTION DESCRIPTION
BC 412 with Virtual
Applies the SEMI-standard barcode checksum and the Cognex Virtual checksum. If the read result
passes the BC 412 checksum, 200 points are added to the raw score. If the read result also
passes the Virtual checksum and the results from both checksums agree, an additional 100 points
are added to the score.
The read must pass both the SEMI BC 412 and Virtual checksums to be successful; if either
checksum fails, the entire read will fail.
This selection is typically used when the character string is marked directly below the barcode on
the wafer.
Maximum score: 400 points
Minimum passed score: 300 plus Accept threshold
IBM 412 with Virtual
Applies the IBM barcode checksum and the Cognex Virtual checksum. If the read result passes
the IBM 412 checksum, 200 points are added to the Raw Score. If the read result also passes the
Virtual checksum and the results from both checksums agree, an additional 100 points are added
to the score.
The read must pass both the IBM 412 and Virtual checksums to be successful; if either checksum
fails, the entire read will fail.
This selection is typically only used when the character string is marked directly below the barcode
on the wafer.
Maximum score: 400 points
Minimum passed score: 300 plus Accept threshold
3.4.6 Field String and Field Definition
The Field String and Field Definition settings work together to define the format of the
character string when ‘Chars, SEMI’, ‘Chars, IBM’, ‘Chars, Triple’, or one of the barcodes
is the selected Mark type.
NOTES
■ Both The Field String and Field Definition settings are case sensitive.
■ When ‘Chars, IBM’ is the selected Mark, the only valid characters are Hexadecimal.
■ When ‘2D Code, T7’ is the selected Mark, the Field String and Field Definition settings are ignored.
Field String
The Field String specifies the number of characters contained in the character string or
encoded in a barcode, including alphanumerics (A-Z, 0-9), dashes (-), dots (.), and
spaces.
Each character in the Field String corresponds to an indexed field position between 0 and
21. The Field String must contain the same number of positions as there are characters
in the wafer mark for the read to pass. By default, each position in the Field String is
represented as an asterisk (*) character, or alphanumeric “wildcard.” This means that any
character A-Z or 0-9 is valid at any position in the string.
However, an individual position in the Field String can be limited to consider only a
subset of possible characters at that position. This increases overall performance and
reliability because characters that are not possible at a position will not be considered
during a read. The following table lists predefined “field definitions” that can be entered in
the Field String:
