Cognex In-Sight 1721, User Manual

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In-Sight
®
1700 Series Wafer Reader Section 3: Configuring a Wafer ID Application
27
3.5.6 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 Sym, T7 Data Matrix’ is the selected Mark, the Field String and Field Definition settings
are ignored.
Field String
The Field String specifies the characters, and 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.
NOTE For compressed barcodes, the field string is the actual number of encoded characters, not the
number of characters that are expected to be returned. For example, a compressed barcode may
contain 7 encoded characters, but return 11 characters when the barcode is read. Therefore, 7
characters would be entered in the field string.
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:
FIELD STRING
ENTRY
DEFINITION VALID CHARACTERS
* Alphanumeric wildcard ABCDEFGHIJKLMNOPQRSTUVWXYZ
0123456789
A Alpha ABCDEFGHIJKLMNOPQRSTUVWXYZ
N Numeric 0123456789
H Hexadecimal 0123456789
ABCDEF
D Decimal 0123456789
(.)
C SEMI Checksum, alpha ABCDEFGH
S SEMI Checksum, numeric 01234567
X Alphanumeric wildcard, alpha, numeric,
hexadecimal, decimal, SEMI Checksum, dot and
dash
ABCDEFGHIJKLMNOPQRSTUVWXYZ
0123456789
(.)
(-)