Prog Mode Does Not Change To Run; Alarm Led Turns On On The Cpu Unit - Panasonic AFP7PSA1 User Manual

Troubleshooting

6.2.2 PROG Mode Does Not Change to RUN

 Condition:
A syntax error or a self-diagnosis error that caused operation to stop has occurred.
 Solution:
Confirm the status in the following procedure.
PROCEDURE
1. Confirm that the ERROR or ALARM LED is not turned on.
2. Use the "Totally Check Project" function under "Debug" in FPWIN GR7 to
identify the syntax error.

6.2.3 ALARM LED Turns ON on the CPU Unit

 Condition:
The system watchdog timer has been activated and the operation of controller has been
stopped.
 Solution:
PROCEDURE
1. Switch the CPU unit to the PROG. mode, and turn off the power supply and
then on again.
If the ALARM LED lights again, there may be a problem with the unit. If the
ALARM LED goes out after the power supply is turned off and then on again, the
problem may have been caused by noise or another temporary phenomenon.
2. Switch to the RUN mode.
If ALARM LED turns on after switching to the RUN mode, the program is taking
excessive time. Review and modify the program.
3. Check the ambient environment for influence of noise.
If there is no problem with the program, there may be a problem in the ambient
environment. Check the wiring including the earth wiring. In particular, check if the
RS-232C wiring is not close to power cables, and if the wiring is shielded.
KEY POINTS

When the program is to be reviewed, check the following points.
Example 1: Is there any infinite loop in the program, resulting from a JP
instruction, LOOP instruction or other instructions that control the program
flow?
Example 2: Are there multiple interrupt instructions that are being
consecutively executed?
6-4
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