Mitsubishi Electric MELSEC iQ-R Series User Manual page 147

When the self-tuning does not start
When the self-tuning does not start (CH Auto tuning status (X4 to X7) does not turn ON), check the following items:
Check item
Have the self-tuning start conditions been met?
Has the self-tuning ended abnormally?
When 'Setting value backup failure flag' (XA) is ON
When 'Setting value backup failure flag' (XA) is ON, check the following items:
Check item
Has backing up data to the non-volatile memory
failed?
Has reading data from the non-volatile memory
failed?
When 'CH Alert flag' (XC to XF) is ON
When CH Alert flag (XC to XF) is ON, check the following items:
Check item
Has the temperature process value (PV) exceeded
the alert set value range?
Has a disconnection been detected?
When the temperature process value (PV) is abnormal
When the temperature process value (PV) is abnormal, check the following items:
Check item
Is the thermocouple wiring resistance value too
high?
Corrective action
Refer to Self-tuning Function and check whether all the conditions have been met. ( Page 47 Self-
tuning Function)
Refer to Conditions where self-tuning ends abnormally and check whether the auto tuning has ended
abnormally. If it has ended abnormally, remove the cause. If the buffer memory setting was changed
during self-tuning, restore the value to the one prior to change. ( Page 47 Self-tuning Function)
Corrective action
Turn from OFF to ON on 'Setting value backup command' (Y8) and write data to the non-volatile
memory.
When writing data fails again, a hardware failure has occurred. Please contact your local Mitsubishi
Electric sales office or representative.
Corrective action
• Check CH Alert definition and take the appropriate corrective action. ( Page 230 CH1 Alert
definition)
• Check and change the alert set value. ( Page 248 CH1 Alert set value 1)
Check CH Alert definition and take the appropriate corrective action. ( Page 230 CH1 Alert
definition)
Corrective action
• Check the thermocouple wiring resistance value and check whether a difference in the temperatures
was caused by the wiring resistance. (MELSEC iQ-R Temperature Control Module User's Manual
(Startup))
• Use the sensor correction function to correct the difference in the temperatures caused by the wiring
resistance. ( Page 59 Sensor Correction Function)
3 TROUBLESHOOTING
3.3 Troubleshooting by Symptom
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