Rockwell Automation 1772-LS_LSP,D17726.8.6 PROG/OPER MANUAL-MINI PLC-2/05 - Manual (Page 47)

Memory Organization
Chapter 4
4Ć9
Message Storage Area
The third major part of memory is the message storage area (Figure 4.2). You
can print out messages in hard copy form. You can store up to 70 messages
using the 1770-T3 industrial terminal, or 198 messages using the 1770- T3
terminal with the 1770-RG module.
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 are 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
is activated.
Address 027 controls messages 1-6. You designate control words which control
your messages in groups of 8. Your control word must be arranged in
consecutive order.
Report generation (see chapter 17) 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 any other functions if you want to achieve maximum flexibility within
your program.
We described detailed concepts of memory organization and its structure. The
next chapter explains how the processor scans the program.
Chapter Summary