Mitsubishi Electric MELDAS 600M Series Instruction Manual page 436

8. Fault Diagnosis and Action
8.1 Checking the fault occurrence status
Check the following:
• When did the fault occur?
• During what operation did the fault occur?
• What fault?
(1) When did the fault occur?
Time of day when the fault occurred.
(2) During what operation did the fault occur?
What NC operation mode?
• For automatic operation ...... Program number, sequence number, and contents of program
• For manual operation .............. Mode?
• Setting and display unit's screen?
• During I/O operation?
• Machine system status?
• During tool change?
• Controlled axis hunting?
(3) What fault occurred?
• What does the alarm display of the setting and display unit's alarm diagnosis screen indicate?
• What does the machine sequence alarm indicate?
• Is the LCD screen normal?
(4) Frequency of fault?
• When did the fault occur? Frequency? (Did the fault occur during operation of another
• In specific mode?
• When the ceiling crane moved?
• Frequency for the same kind of workpiece?
• Does the fault occur when the same operation is made?
• Change the conditions (override, contents of program, operating procedure, etc.). Does the
• What was the ambient temperature?
• Was there a contact defect or insulation defect on the cable?
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CHAPTER 3 MAINTENANCE
8. Fault Diagnosis and Action
Display the alarm diagnosis screen to check the contents of alarm.
machine?) If the frequency is too small, or the fault occurred during operation of another
machine, the cause may be noises of the supply voltage, for example. In this case, check that
(i) the supply voltage is normal (does momentary drop occur during operation of another
machine?) and (ii) measures have been taken against noises.
(Repeatability check)
same fault occur?
(Was there a sudden temperature change? Was the fan on the top of the control unit
working?)
(Was there any oil or cutting water splashed on the cable?)
search engine
Operating procedure?
Preceding and succeeding operations?
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