FANUC 0i-D alarm and operation histories: what to save after a fault

The difficulty with intermittent faults is that the alarm may have disappeared before repair personnel arrive. A normal screen does not mean the cause is understood. A more useful first step than repeated restarts is to preserve the complete alarm and surrounding records, whenever viewing is permitted, to establish a reviewable sequence.

What each history can tell you

This example follows the 0i-D/0i Mate-D operator’s manual B-64304EN/02. Its alarm history retains up to the latest fifty entries, discarding the oldest when capacity is exceeded; access is through HISTRY under MESSAGE. Operation history may record key presses, selected input/output signal changes, alarms and other events. Actual coverage depends on configuration and recording conditions. It is not a complete recording of every machine action.

Save the current alarm before looking for the preceding event

1. Photograph the full screen, retaining the alarm category, number, text and axis or path identifier, not merely the last digits. If an amplifier also has a display, separately photograph its location and displayed indication.
2. Review the preceding and following alarm-history pages and save relevant records on both sides of the fault. On multi-path machines, identify the path to which each record belongs; identical alarm numbers do not necessarily describe one event.
3. Record the actual time on site and compare it with the system clock. Note any discrepancy; do not change the clock first and then try to reconstruct the sequence.
4. If operation history is available, save the same time interval, adding the operation being performed and whether the operator was changing tools, starting or stopping the spindle, or switching modes.

No record does not mean “it did not happen”

History capacity is limited, and relevant signals may not have been selected for recording. A blank page only shows insufficient currently visible evidence; it cannot rule out power, interface or operating factors. Changing recording conditions to reproduce a fault is a separate maintenance task. Preserve the current state first, then have someone familiar with the machine configuration plan the capture.

Separate assumptions from confirmed facts

For example, “the battery was replaced just before the alarm” is a timing clue, not proof of causation. “It recovered after reset” describes that occasion, not a completed repair. A handover can use four columns: symptoms, recent actions, checks completed and matters still unconfirmed. This reduces repeated tests on the next shift. Clearing history, repeatedly resetting or cycling power before documenting the condition can make comparison harder.

This method organizes evidence; it does not replace the diagnostic procedure for the particular alarm. Use it alongside the machine fault-handling record (Chinese), and consult the FANUC section for the relevant system and model.

References and applicability

• FANUC Series 0i/0i Mate-MODEL D Operator’s Manual B-64304EN/02 (public mirror of the manufacturer’s manual): §7.2, printed page 439; §12.4.13, printed pages 658–663.