Alarm Led Turns On On The Cpu Unit; Power Led Does Not Turn On On The Power Supply Unit - Panasonic FP7 Series User Manual
Cpu unit
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- Command reference manual (1222 pages) ,
- User manual (275 pages) ,
- Additional functions manual (45 pages)
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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:
1.
Switch the CPU unit to the PROG. mode, and turn the power supply off 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.
● When the program is to be reviewed, check the following points.
Example 1: Is the program in infinite loop due to an instruction that controls the flow of the
program, such as a JP instruction or a LOOP instruction?
Example 2: Are interrupt instructions being executed consecutively?
6.2.4 POWER LED Does Not Turn ON on the Power Supply Unit
■
Condition:
It is possible that sufficient power is not supplied.
■
Solution:
Confirm the status in the following procedure.
1.
Power off the unit and double-check the wiring status (e.g. are there any loose terminals?).
2.
Check if output of the power supply unit exceeds the rating.
If capacity of the internal power supply (24V) does not suffice, examine changing
combination of the units.
3.
If the power supply is shared with other devices, disconnect the power supply to the other
devices.
If LED on the power supply unit turns on following the above step, undercapacity of power
supply is possible. Review the power supply design.
WUME-FP7CPUH-09
6.2 What to Do If an Error Occurs
6-5
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