Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 36)

Memory Organization
Chapter 4
4Ć7
The user program area begins at word address 200.
Main Ladder Diagram Program
Purpose: Your program is a group of ladder diagram and functional block
instructions used to control an application.
NOTE: The term ladder diagram is defined in chapter 5.
Description: Refer to chapter 8 section A.
Subroutine Area
Purpose: Used to jump to a defined ladder diagram area. This will allow you
to perform ladder diagram subroutines.
Description: Refer to chapter 6 section B.
Data Highway Instruction
Purpose: Allows you to link up to 64 different stations for data gathering. A
station can be defined as either another processor, computer, or a
communication device.
Description: Programmed in a special format. Refer to our Publication index
(publication SD499) for the list of appropriate publications.
This is the third major part of memory. You are able to print out messages in
hard copy form. You can store up to 70 messages using the 1770-T3 industrial
terminal.
Message storage follows the end statement of your program and is limited by
the number of unused words remaining in memory. Each word stores two
message characters. A character is any alpha or numerical figure (this includes
blank spaces).
Messages can be written to display current data table information such as the
number of parts rejected in a production run for a particular time period. You
can write your program to display messages when a pushbutton switch or
industrial terminal key is activated.
Address 027 controls messages 1-6. You designate control words which store
your messages in groups of 8. Your control words must be arranged in
consecutive order.
Report generation is a function of your message control words. Reserve bit
addresses 02710 thru 02717 for this automatic report generation function to
determine status of this function. These bit addresses should not be used for
Message Storage