10.Troubleshooting
10.1.2CPU check
If the PWR (power) LED is lit but the RUN LED is not lit, check the following points.
Check the position of the
mode control switch
Check the FLT (fault) LED
Is the RUN LED blinking ?
Connect the programming tool, and check the T1/T1S’s status
If it is not in R (RUN) position, turn the switch to R (RUN) position.
If the FLT LED is lit or blinking, the T1/T1S is in the ERROR mode. Confirm the error message by connecting the programming tool. Refer to section 10.2.
If it is blinking, the T1/T1S is in the HOLD mode. Check your program whether the HOLD device (S401) is not used.
If the T1/T1S stays in HALT mode even when the mode control switch is changed, the switch may be faulty.
If the communication between the T1/T1S and the programming tool is not possible, the T1/T1S may be faulty.
10.1.3Program check
Check the user program based on the following points if it is running but the operation does not work as intended.
1.Whether duplicated coils are not programmed.
2.Whether a coil device and a destination of a function instruction are not overlapping.
3.Whether the ON/OFF duration of an external input signal is not shorter than the T1/T1S’s scan time.
4.Whether a register/device which is used in the main program is not operated erroneously in the interrupt program.
NOTE
When you write/modify the program, it is necessary to execute the EEPROM write operation before turning off power to the T1. Otherwise the old program stored in the
296 T1/T1S User’s Manual
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