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284 T1-16S User’s Manual
10. Troubleshooting
10.1.2 CPU check
If the PWR (power) LED is lit but the RUN LED is not lit, check the following points.
Check the position of the If it is not in R (RUN) position, turn the
mode control switch switch t o R (RUN) position.
Check the FLT (fault) LED I f the FLT LED is lit or bli nk i ng, the T1-16S
is in the ERROR mode. Confirm the error
message by connecting the
programming tool. Refer to section 10.2.
Is the RUN LED blinking ? If it is blinking, t he T1- 16S i s in the HOLD
mode. Check your program
whether the HOLD device (S401) is
not used.
Connect the programming If the T1-16S stays i n HALT mode even
tool, and check the T1-16S’s when the mode control switch is changed,
status the swit ch may be faulty.
If the communicat ion between the T1-16S
and the programming tool is not pos sible,
the T1-16S may be faulty.
10.1.3 Program 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
T1-16S’s scan time.
(4) W hether a register/devic e , which is used in the main program , is not operated
erroneously in the interrupt program.
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 built-in EEPROM will be over-written, and your
program modification will disappear.
NOTE