Rockwell Automation 2706-LV2P_LV2R_LV4P_LV4R DL40 PLUS USER MANUAL - Manual (Page 45)

Using the Onboard Editor to Create Messages 2–19
Publication 2706-6.1
The message queue of the DL40 Plus stores message triggers in the
order received for subsequent running and/or display. The queue
ensures that triggered messages are not lost when preceded by
messages with long wait times, ASCII inputs, or the acknowledge
attribute set.
Message Queue Enabled
When the message queue is enabled, the queue stores a maximum of
20 message triggers for subsequent display. The queue is a
first-in-first-out (FIFO) buffer and stores message numbers as
follows:
1st Msg
Triggered 2nd Msg
Triggered 3rd Msg
Triggered 18th Msg
Triggered 19th Msg
Triggered 20th Msg
Triggered . . .
1 2 3 18 19 20 Queue Entry Number
Queue Contents
First Msg in Queue
Top message in queue is the
next message to be displayed
•
Messages are run or displayed from the top of the queue
•
Messages move toward the top of the queue when previous
messages are run or displayed
•
Message triggers occurring when the queue is full (20 entries) are
lost
Message Queue Disabled
When the message queue is disabled, the queue will only store 1
message trigger besides the currently displayed message. Message
triggers beyond the next trigger (1 entry) are lost.
Next Msg
Triggered
1 Queue Entry Number
Queue Contents
Displayed Message
Message in the queue is the
next message to be displayed
Message Queue