Rockwell Automation 2706-LV2P_LV2R_LV4P_LV4R DL40 PLUS USER MANUAL - Manual (Page 125)

Remote I/O Communications 8–33
Publication 2706-6.1
Sections of a Bit Trigger Table
The Bit Trigger table has 3 sections (all sent with a single transfer):
•
Priority Message Number
•
Priority
•
Round Robin
Priority Message Number Section
When a priority message trigger is received (via Remote I/O,
RS-485, RS-232, or Keyboard Port), it is queued as in the
Message/Variable/Slave run mode.
After the current message runs, priority messages in the queue run.
•
If no bits in the Priority or the Round Robin section changed, the
DL40 Plus returns to where it left off (in either section) and
resume running messages.
•
If any bit in the Priority or the Round Robin section changed, the
DL40 Plus returns to the start of the Priority Section to resume
running messages.
The priority message can be any message including a special
message. Send the number of the message you want to trigger in the
Priority Message Number section of the Bit Trigger Table. If you
don’t want to trigger a priority message, leave this part of the table
empty (
= 0).
Priority Section
Messages in this section are prioritized, starting with message
number 1 (corresponding to bit 00 of Word 1). This message has the
highest priority. The message with the highest priority (that has its
corresponding bit set) is displayed first. After the highest priority
message has run, the message with the next highest priority (with its
bit set) is displayed. The DL40 Plus continues to run through the
Priority Section displaying messages until the message
corresponding to the last set bit in this section is displayed.
Messages are displayed once for each change to the Bit Trigger table.
If an updated table (with a new Priority Message Number or at least
one bit in either the Priority Section or the Round Robin Section
changed) is sent to the DL40 Plus, the messages of the new Bit
Trigger Table run immediately even if messages in the old Bit
Trigger Table did not run. Messages with low priorities may never be
displayed. After the DL40 Plus displays all the messages in the
Priority Section (with bits set), the messages in the Round Robin
Section are displayed.
Note: The size (in words) of the Priority Section is set with the
Onboard Editor or with the Offline Programming Software.