User Manual Owner's manual

Program Troubleshooting
Chapter 26
26-2
Diagnosing a Run T ime 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 T ime 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 nonexistent I/O rack number.
Incorrect block length value.