If The Run Led Has Flickered Or Turned Off; If The Err. Led Has Turned On Or Flickered - Mitsubishi Electric MELSEC Q Series User Manual

8 TROUBLESHOOTING

8.3 If the RUN LED Has Flickered or Turned Off

8.4 If the ERR. LED Has Turned On or Flickered

8.5 If the ALM LED Has Turned On or Flickered
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Check item
Is 5VDC supplied?
Is the sum of current capacities of the modules
loaded on the base unit equal to or less than
the current capacity of the power supply
module?
Has a watchdog timer error occurred?
Is a module change enabled during an online
module change?
(1) If turned on
Check item
Is the cold junction temperature compensation
resistor disconnected?
(2) If flickered
Check item
Has a write data error occurred?
(1) If turned on
Check item
Has the alert occurrence flag (XnC to XnF)
turned on?
(2) If flickered
Check item
Is the process value beyond the measured
temperature range specified for the input
range?
Is there any channel where a thermocouple is
not connected?
Has a loop disconnection been detected?
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MELSEC-Q
Corrective action
• Check the power supply module.
• Load the module securely.
Make the sum of current capacities of the
modules loaded on the base unit equal to or
less than the current capacity of the power
supply module.
• Reset the programmable controller CPU or
power it on again.
• Change the Q64TC.
Refer to Chapter 7 and take corrective action.
Corrective action
• Connect the cold junction temperature
compensation resistor.
• The Q64TC hardware fault.
Please consult your sales representative.
Corrective action
• Check the error code list in Section 8.1 and
correct the sequence program.
Corrective action
• Check the alert definition (buffer memory
address: 5 to 8 ) and take action for the
H H
alert that occurred.
Corrective action
• Change the input range setting to the
operating temperature range setting.
• Set the channel where a thermocouple is not
connected as unused to the unused channel
setting (buffer memory address: 3D
7D , 9D ).
H H
• Check for a load disconnection, external
operation device fault, sensor disconnector
or the like.
, 5D ,
H H
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