Rockwell Automation 2755 AtomScan Bar Code Reader - Manual (Page 55)

5–10 Configuring Your Reader
Publication 2755-6.9
•
Triggering Mode. Allows you to establish the type of trigger
event that will initiate or end the read cycle. The trigger event
options are listed in the following table.
Parameter Description
Continuous Read
Trigger input options are disabled and the reader is always in the read cycle. Bar
code data is decoded, and label information is transmitted repeatedly, as long as the
label is in the read range of the reader. When To Output options have no affect on
Continuous Read. Continuous Read is useful in testing label or reader functions.
If both Continuous Read and Match Code are enabled the reader defaults to
Continuous Read, 1 Output mode.
Continuous Read, 1
Output
Label data is immediately transmitted once every time new label data is placed in
front of the reader. With Timeout enabled for End Of Read Cycle, if the label doesn’t
change, the reader will repeat the output at the end of each subsequent timeout
period. For example, if Timeout were set to one second, the reader would output the
label data immediately, and then repeat the output at intervals of one second, for as
long as the label continued to be scanned.
With Timeout disabled (that is, End Of Read Cycle set to New Trigger), the reader
will output the current label data immediately, but output it only once. A new label
appearing at any time in the scan range will produce a new read output as long as
the new label is not identical to the previous label.
Enabling Continuous Read, 1 Output when Number of Labels is set to any number
greater than one will cause Number of Labels to default back to one.
External Level
Allows a read cycle to be initiated by a trigger signal from a package detector when a
package appears within the detector’s range. The read cycle exists as long as the
detector “sees” the package and ends when the package moves out of the detector’s
range
➀ .
External Edge
As with Level, Edge allows a read cycle to be initiated by a trigger signal from a
package detector when it detects the appearance of a package (rising edge). But
unlike Level mode, the removal of a package (falling edge) does not end the read
cycle. With Edge enabled, the read cycle ends with a good read output, a timeout,
or a new trigger.
Serial Data
The reader accepts an ASCII character from the host or controlling device as a
trigger to start a read cycle. Serial data trigger behaves the same as External Edge.
Serial Data and
External Edge The reader accepts either an external trigger or a serial ASCII command to start a
read cycle.
➀
Level and Edge apply to the active logic state (positive or negative) that exists while the package
is in a read cycle, between the rising edge and falling edge. Rising edge is the trigger signal
associated with the appearance of a package. Falling edge is the trigger signal associated with
the subsequent disappearance of the package.