Program Troubleshooting
Chapter 26
26-2
Diagnosing a Run Time Error
The following steps help you diagnose run time errors:
1.
Connect your industrial terminal to the processor.
2.
Turn on the industrial terminal and notice the message, PLC-2
RUN-TIME ERROR. Press [1] [1] to continue. If the industrial
terminal is already connected, then your ladder diagram is replaced
by the display showing the run time error message on the mode
selection screen.
3.
Press [1] [1] to display the instruction that caused the error.
4.
Correct the run time error by editing your program (Table 26.A).
5.
Restart your processor.
Table 26.A
Possible Causes of Run Time Errors
Instruction
Cause
Jump
Jumping from the main program into the subroutine area or vice versa.
Jumping backwards.
Omitting the label instruction corresponding to the jump instruction.
Jumping over a temporary end instruction.
Label
Multiple placement of the same label identification number.
Removing a label instruction but leaving its reference, the jump or
jump to subroutine instructions.
Jump to subroutine
To begin your main program.
To jump forward in your main program.
Use in the subroutine area.
Omitting a return instruction.
Omitting a corresponding label instruction.
Jumping over a temporary end instruction.
Return
Processor does not find a return instruction from the subroutine area.
Using a return instruction outside the subroutine area.
Files
AC>PR
Duplicating counter's address.
Manipulating the counter's accumulated value by means of external
programming equipment or data highway hardware.
Sequencer
File address is out of range.
Preset value equals 0.
Block transfer
Giving the module address a nonexistent I/O rack number.
Incorrect block length value.
