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6. TROUBLESHOOTING
6.
TROUBLESHOOTING
6.1
Cause of Errors and Corrective Actions by LED Indication
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The general troubleshooting methods for using AJ65BT-68TD is explained below.
The following describes the error confirmation method using the LEDs on AJ65BT-68TD.
For the errors associated with the programmable controller CPU and master module, refer to the
user's manual for the programmable controller CPU and master module, respectively.
(1) When AJ65BT-68TD's "RUN" LED is off
Cause
Watchdog timer error occurred.
24 V DC power is not supplied to AJ65BT-68TD,
or voltage is insufficient.
At test mode, the offset/gain setting switch is
positioned at SET.
(2) When AJ65BT-68TD's "RUN" LED flikers at 0.5-second intervals
Cause
At test mode, the offset/gain setting switch is
positioned at OFFSET or GAIN.
(3) When AJ65BT-68TD's "RUN" LED flikers at 0.1-second intervals
Cause
The all-channel-batch thermocouple selection is
overlapped.
Or, if a thermocouple is selected for each
channel, the selection of a thermocouple is
overlapped for the same channel.
A value out of the allowable setting range was
set for the upper and lower limit of the
temperature measurement range, or the upper
limit value is smaller than or equal to the lower
limit value.
The offset or gain value set in the test mode is
out of the allowable setting range.
Or, the gain value minus offset value is smaller
than 10°C.
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Corrective action
Confirm the watchdog timer error with the master module's
special link register, then restart the power to AJ65BT-68TD *1.
If "RUN" LED does not come on after power restart, contact the
nearest representative or branch regarding the problem, as
hardware may be faulty.
Check the voltage of 24 V DC power supply.
After setting offset/gain, position the mode switch to 0
(NORMAL).
Corrective action
After setting offset/gain, position the mode switch to 0
(NORMAL).
Corrective action
Verify the thermocouple selection, then set a valid
thermocouple using the initial data and switch on the error reset
request flag (RY(n+7)A).
Verify the channel in which a write error has been occurred
using the write data error flag, then set a valid value using the
initial data and switch on the error reset request flag
(RY(n+7)A).
Verify the allowable setting range and set a valid offset or gain
value.
Or, set the offset and gain values so that the gain value minus
offset value is greater than or equal to 10°C.
6-1
MELSEC-A
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