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Rockwell Automation 1772-LP3 PLC - 2/30 Programmable Controller Programming and Operations Manual User Manual

Page 85

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Introduction to Programming

Chapter 4

4Ć21

the instruction will be inserted before the END statement or subroutine
area.

The other way to insert an instruction is to press the key sequence
[INSERT] [

] [Key sequence of instruction] [Key sequence of address].

The new instruction will be inserted before the cursor’s present position.

Bit addresses of 6 or 7 digits can be entered provided the data table is
expanded to a 4- or 5-digit word address and the [EXPAND ADDR] key is
used.

If, at any time, the memory is full, the instruction cannot be entered and a
MEMORY FULL message will be displayed.

Removing an Instruction

Only nonoutput instructions can be removed from a rung. Output
instructions can be removed only be removing the complete rung.

To remove an instruction, place the cursor on the appropriate instruction
and press the key sequence [REMOVE] [Key sequence of instruction]. Bit
values and data of word instructions are not cleared. The input image table
bits will be rewritten during the next I/O scan. If the wrong instruction is
pressed, an INSTRUCTIONS DO NOT MATCH message will be
displayed.

Inserting a Rung

A rung can be inserted anywhere within a program by pressing
[INSERT][RUNG] and entering the instructions. The cursor must be
positioned on any instruction of the previous rung. The new rung will be
inserted after the rung which contains the cursor. If the cursor is on the
END statement, the rung need not be inserted. It can be entered just as in
initial program entry. Instructions in the new rung cannot be edited until
the rung is complete.

If, at any time, the memory is full, a MEMORY FULL message will be
displayed and more instructions will not be accepted.

Removing a Rung

Removing a rung is the only way an output instruction can be removed.
Any rung, except the last one containing the END statement, can be
removed.

To remove a rung, position the cursor anywhere on that rung and press
[REMOVE][RUNG]. Only bits corresponding to output energize latch or