Rockwell Automation 1772-LV,D17726.6.1 A and I MNL MINI-PLC-2/15 PROCESSO - Manual (Page 82)

Maintenance and Troubleshooting
Chapter 5
5Ć12
nature of the problem. The possible combinations of indicator status are
summarized in Table 5.B.
Processor Faults and Run-Time Errors
Any time the PROCESSOR indicator goes ON by itself during operation, this
indicates that a hardware fault in the Processor has occurred. The only way to
correct this type of fault is by cycling line power using the main disconnect or
by replacing the Processor.
Any time the MEMORY indicator goes ON by itself or with the PROCESSOR
indicator, this can indicate either a processor fault or a run–time error. The first
step in diagnosing the fault is to connect the 1770–T3 Industrial Terminal to the
Processor. Once connected and turned ON, the Industrial Terminal will display
a message that identifies the fault as a processor fault or a run–time error.
If both indicators are illuminated, the processor fault can be corrected by
turning the Mode Select Switch to PROG and back to RUN or RUN/PROG or
by replacing the Processor.
If the fault is a run–time error, press [1][1] for PLC–2 mode. The Industrial
Terminal will display the rung and intensify the instruction where the run–time
error occurred. This instruction could be the cause or the effect of the
programming error. In addition, the type of run–time error will be described
near the bottom of the screen.
Correcting Run-Time Errors
Familiarity with the Mini–PLC–2/15 instruction set is required for correcting
errors in the program. All Mini–PLC–2/15 instructions are described in the
Programming and Operations Manual (Publication 1772–84). Refer to this
Manual as needed for information on the program instructions and correcting
run–time errors.
Run–time errors are corrected with the Processor in the PROG or REMOTE
PROG mode. If the error occurred with the Processor in the RUN/PROG mode,
connecting the Industrial Terminal will automatically place the Processor in
REMOTE PROG mode. If the Processor is in the RUN mode, the Mode Select
Switch must be changed to the PROG position to make the correction.
When a programmed EPROM is in place in the Processor, follow these
procedures to make corrections to the program.