Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 98)

7–10 Configuration: Scanner Control, Primary Match Table, Discrete I/O
Publication 2755-833
In Independent Package Detect mode, the Symbols/Package
setting must be satisfied by each scanner individually. For
example, the Symbols/Package setting is 2. Scanner A must decode
two symbols to produce a valid read, or scanner B must decode two
symbols to produce a valid read. If both scanners are triggered from
their respective package detects, and Scanner A decodes only one
symbol and Scanner B decodes only one symbol, two packages will
be sent to the host with a no-read indicated in each.
In Independent Host Command mode, the decoder starts and
stops decoding symbols as instructed by a host computer. For
example, the Symbols/Package setting is 2. Scanner A must decode
two symbols to produce a valid read, or scanner B must decode two
symbols to produce a valid read. If both scanners are triggered using
their respective Start Scan and Stop Scan characters, and Scanner A
decodes only one symbol and Scanner B decodes only one symbol,
two packages will be sent to the host with a no-read indicated in
each.
The following example illustrates the difference between
Coordinated 1 and Coordinated 2 modes, and how the
Symbols/Package setting affects scanner operation in both the
Coordinated and the Independent modes.
Scanner A reads 1234 Scanner B reads ABCD
Symbols/Package = 2
Independent Modes Coordinated 1 Mode
/1234/No–Read//
/ABDC/No–Read// /1234/ABCD//
In this example the field delimiter is the “ /”, source identifiers are ScnA and ScnB for
scanner A and B respectively, and the default no-read message is “No-Read”.
Coordinated 2 Mode
/1234/ABCD//
Scanner A reads 1234 Scanner B reads 1234
/1234/No–Read//
/1234/1234// /1234/No-Read//
Scanner A reads 1234 Scanner A reads ABCD
/1234/ABCD// /1234/ABCD// /1234/ABCD//
Example #1
Example #2
Example #3
ScnA
ScnB
ScnA ScnA
ScnA ScnA
ScnA ScnA ScnA
ScnB
ScnB/No-Read/No-Read//
/1234/No–Read// ScnA