Справочник Пользователя для Mitsubishi Electronics FX3S-5DM

FX

3S

 Series Programmable Controllers

User's Manual - Hardware Edition

14 Test Operation, Adjustment, Maintenance and Troubleshooting

When trouble occurs, check the LEDs on the PLC to identify the problem with the PLC.

On

Power of the specified voltage is being correctly
supplied to the power supply terminal.

The power supply is normal.

Flashing

One of the following problems may have occurred.
•

Power of the specified voltage and current is not
being supplied to the power supply terminal.

•

External wiring is incorrect.

•

Internal error of PLC

•

Check the supply voltage.

•

After disconnecting the cables other than the power cable, re-
apply power to the PLC, and check for changes in the state. If the
problem persists, consult your local Mitsubishi Electric
representative.

Off

One of the following problems may have occurred.
•

The power supply is off.

•

External wiring is incorrect.

•

Power of the specified voltage is not being
supplied to the power supply terminal.

•

The power cable is broken.

•

If the power is not off, check the power supply and the power
supply route.

•

If power is being supplied correctly, consult your local Mitsubishi
Electric representative.

•

After disconnecting the cables other than the power cable, re-
apply power to the PLC, and check for changes in the state. If the
problem persists, consult your local Mitsubishi Electric
representative.

On

A watchdog timer error may have occurred,
or the hardware of the PLC may be
damaged.

1) Stop the PLC, and re-apply power. 

If ERR LED goes off, a watchdog timer error may have occurred. Take
any of the following measures.

-

Review the program. 
The maximum value (D8012) of the scan time should not exceed the 
setting (D8000) of the watchdog timer.

-

Check that the input used for input interruption or pulse catch is not 
being abnormally turned on and off in one scan.

-

Check that the frequency of the pulse (duty of 50%) input to the high-
speed counter does not exceed the specified range.

-

Add the WDT instructions. 
Add some WDT instructions to the program, and reset the watchdog 
timer several times in one scan. 

-

Change the setting of the watchdog timer. 
Change the watchdog timer setting (D8000) in the program so that the 
setting is larger than the maximum value of the scan time (D8012).

2) Remove the PLC and supply power to it from another power supply on a

desk. 
If the ERR LED goes off, noise may have affected the PLC. 
Take the following measures.

-

Check the ground wiring, and reexamine the wiring route and 
installation location.

-

Fit a noise filter onto the power supply line.

3) If the ERR LED does not go off even after the measures stated in (1) and

(2) are taken, consult your local Mitsubishi Electric representative.

Flashing

One of the following errors has occurred in
the PLC.
•

Parameter error

•

Syntax  error

•

Ladder error

Perform PLC diagnosis and program check with the programming tool.
For the remedies, refer to Section 14.6.

Off

No errors that stop the PLC have occurred.

If the operations of the PLC are abnormal, perform PLC diagnosis and
program check with the programming tool.
A Serial communication error or Operation error may have occurred.