Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 33)

Memory Organization
Chapter 4
4Ć4
transfer of output data to output devices occur during I/O scan. If the status of
the output instruction changes in the program then the on/off status of the output
devices update during the I/O scan to reflect the change.
To utilize the data table to its fullest capacity certain facts must be understood:
The processor automatically reserves the first 128 words in the memory for
the data table.
You can increase the data table size in two word increments up to 256 words.
Then you can increase in blocks of 128 words.
When the data table is set to 256 words, you can program up to 104
timer/counter instructions. These instructions are explained in chapter 5
section C.
The data table can be changed in size from 48 words to 1,920 words using
the industrial terminal.
Adjusted Data Table
You can adjust the data table size from the factory adjusted size of 128 words.
This type of action is called reconfiguration. Using the 1770-T3 industrial
terminal the data table can be adjusted in size from 48 words to 1920 words.
Expanding the data table provides additional timers/counters and space for files
(see chapter 5 for timers/counters and chapter 6 for file information), but your
program storage and message areas will be reduced.