Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 101)

7–13 Configuration: Scanner Control, Primary Match Table, Discrete I/O
Publication 2755-833
If the filter is enabled, the decoder starts a timer whenever it senses a
package detect signal longer than 1 millisecond. This timer delays
the decoder’s reaction to the package detect for between 10 and 15
milliseconds to allow any “bounce” in the signal level to settle. If the
package detect signal is still present when the timer expires, the
decoder will begin to process the package. Package detect signals
shorter than 10 milliseconds will be ignored by the decoder when
the filter is used. Because of timer resolution, package detects
between 10 and 15 milliseconds may be ignored.
The filter likewise reacts to the loss of the package detect signal.
When the signal is lost for a minimum of 1 millisecond, the filter
will maintain the trigger for 10 to 15 milliseconds. The resultant
trigger period length will be equal to the package detect period
5
milliseconds.
Note: This parameter applies only when Scanner B is operating in
independent mode. (See Scanning Mode under Scanner B Control.)
Package Detect Input B Sense
Field Type Options
Select
Lo = Package
Hi = Package
Determines whether a package on Scanner B is detected when the
voltage at the package detect input is high or low. The default is
LO=Package.
Note: This parameter applies only to Scanner B and only when
Scanner B is operating in an independent mode. (See Scanning Mode
under Scanner B Control.)
Primary Match Table Parameters
These parameters define match code entries in the primary match
code table. You can define up to eight entries here (and another 128
entries in the extended match code table described later). Each table
entry has two parameters:
•
symbology of match code string
•
match code string
Each parameter is defined below. The options for each parameter are
summarized in a table, and explained more fully in the text. The
default setting for each parameter is displayed in bold letters in the
table.