Rockwell Automation 2755-DM9, -DM9E High Speed Decoder - Manual (Page 27)

Chapter 3
How the Decoder Operates
3–8
In the triggered mode of operation, there are three possible trigger sources:
•
Host command - The command is generated by a host computer or
programmable controller.
•
Package detect - A package detector connected to the scan head is the
source for the trigger.
•
Internal timer - The internal timer cycles the trigger from on to off based
on a timed interval.
When a trigger on is received, the decoder will continuously attempt to
decode bar codes until one of the following trigger ending conditions occurs:
(a) The number of fields (bar codes) per package count is satisfied.
(b) A trigger off command is sent by a host device.
(c) Package detect signal is no longer present.
(d) The internal timer (No-Read timer) times out.
In the triggered mode of operation there are two options which determine
when the decoder will send bar code information to a host and/or operate
discrete outputs:
•
After Valid Package - A valid package is a package that has valid bar
code symbols and meets the fields (bar codes) per package count
(condition
( a ) listed above).
•
End of Trigger - Refer to trigger ending conditions (b, c, d) listed above.
Trigger Ending Coditions
Response Modes