Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 168)

Troubleshooting Aids
Chapter 13
13Ć4
You can use the temporary end instruction to test or debug a program up to the
point where it is inserted. It acts as a program boundary because instructions
below it in user program are not scanned or operated upon. Instead, the
processor immediately scans the I/O image table followed by user program
from the first instruction to the temporary end instruction.
When the temporary end instruction is inserted, the rungs below it, although
visible and accessible, are not scanned. Their content can be edited, if desired.
The displayed section of user program made inactive by the temporary end
instruction will contain the message “INACTIVE AREA” in the lower right-
hand corner of the screen.
You can insert the temporary end instruction in either of two ways:
Cursor to the last rung of the main program to be kept active. Position the
cursor on the output instruction. Press [INSERT][T.END]
Cursor to the first rung of the main program to be made inactive. Position
the cursor on the first instruction in the rung. Press [INSERT][<-][T.END].
To remove this instruction, position the cursor on it and press
[REMOVE][T.END].
To enter a rung after the temporary end instruction, place the cursor on the
temporary end instruction. Press [INSERT] [RUNG] and then enter the new
rung.
Attempting to use the temporary end instruction in any of the following ways
will either be prevented by the industrial terminal or result in a run-time error.
Using more than one temporary end instruction at a time.
Using the instruction in the subroutine area.
Inserting or removing the instruction during on-line programming.
Placing the instruction in the path of jump or jump to subroutine instructions.
ERR Message for an Illegal Opcode
An illegal opcode is an instruction code that the processor does not recognize.
It causes the processor to fault and is displayed as an ERR message in the ladder
diagram rung in which it occurs. The 4-digit hex value of the illegal opcode is
displayed above the ERR message by the 1770-T3 industrial terminal.
The illegal opcode ERR message should not be confused with ERR messages
caused when a 1770-T1 or -T2 industrial terminal is connected to a processor
that was programmed using a 1770-T3 industrial terminal. Those ERR
messages do not contain the 4-digit hex value and do not cause a processor
fault.
Temporary End Instruction