Rockwell Automation 1747-DTAM-E,D17476.1 Data Table Access Module (DTAM) - Manual (Page 70)

8-10 Message Capability
Publication 1747-6.1
18-Word Message
This is a display and return message. When the message is displayed,
you are required to enter data from the module keypad. It is
functionally similar to the 13-word message except a user-defined
acknowledge bit address block is included to indicate whether or not a
message has been responded to.
The message display format is identical to the 13-word message:
• A signed integer value may be entered using the numeric keys
followed by the >(17(5@ key. When the >(17(5@ key is
pressed, the value is stored at the data entry destination address,
the user-defined message acknowledge bit is set, and the screen
returns to the previous display.
• The message cannot be overwritten while data is being entered.
• Pressing the >(17(5@ key without entering data writes the
initial value to the data entry destination address, sets the
acknowledge bit, and clears the message from the display.
• Pressing the >(6&@ key does not alter the value stored at the
data entry destination address, sets the user defined no
acknowledge bit, and clears the message from the display.
The table on page 8-11 describes the local source file block layout for
the 18-word message. The acknowledge bit address block is
automatically assigned to the five data file address words immediately
following the initial value word.
Important: The programming device does not allocate the memory
location described in the data entry destination address
block OR the acknowledge bit address block. See your
software user manual for information on using the
memory mapping. Otherwise the DTAM displays
,OOHJDO &RPPDQG when it attempts to enter the value
into a non-allocated data entry destination or tries to set
the non-allocated acknowledge bit.