Mitsubishi M800/M80 diagnosis logs: does a missing ALLLOG file-list entry mean no history exists?
Use IB-1501273-L to separate hidden history-output files, collection that stays stopped after power cycling, and the different purposes of /LOG and /LOGEX before clearing fault evidence.
Contents
Refreshing the maintenance I/O file list without finding ALLLOG.LOG does not establish that the control recorded nothing. Mitsubishi explicitly says that ALLLOG.LOG, KEYLOG.LOG and TOUCHLOG.LOG do not appear even after List update. Separately, collection stopped with Stop or Data clear does not resume merely because power is cycled. File-list visibility and active collection require separate checks.
Scope and initial evidence
This article follows the Mitsubishi M800/M80/E80 Series Maintenance Manual, IB-1501273-L, revision L, §§4.11–4.11.4, printed pages 127–133. It covers the diagnosis collection and maintenance I/O functions described there, not automatically M800V/M80V or machine-builder interfaces. Collection operations are protected by operation level; viewing history files on the edit screen requires the password issued by the machine-tool builder. Do not bypass access controls.
First preserve the current alarm, time, control model and version, and a full screenshot of collection settings. The workflow extracts existing evidence; it does not require running the machine to reproduce a fault, changing parameters or clearing records.
Check both states, not only the Alarm history selection
Page 128 displays History data and Sampling data separately. History collecting and History stop indicate whether history collection is running or stopped. Sampling, Sampling stop and Sampling invalid mean sampling is running, stopped or disabled. One line cannot substitute for the other.
The stop-condition table on page 129 says Stop and Data clear stop both history and sampling. When a servo alarm occurs (emergency-stop state) or diagnosis collection stop signal NETSTP has a rising edge, the table lists only Sampling data as the target. Stopped sampling therefore does not by itself establish stopped history; continuing history does not prove sampling continues either.
The general Collecting data select convention is 0: collected and 1: not collected. Alarm history has an explicit exception: its collection starts and stops through Start and Stop regardless of that item's 0/1 value. A selection is not proof of current collection state. Page 129 also says Sampling spec and Collecting data select settings take effect after NC power is turned on again.
Why power cycling may not restore new records
Collection normally starts at NC power-on according to its settings. Once stopped using Stop or Data clear, however, it does not automatically restart at the next power-on. Pages 129–130 specify Start to restart it. Data clear also deletes collected data; it is not a log-refresh button.
Record the stopped state and preserve existing material first. Authorized personnel can then decide whether to restart collection under the builder's procedure. Restarting provides future evidence; it cannot recover an unrecorded past. Do not deliberately generate an alarm to test logging.
Choose the file that answers the question
| File | Manual scope and diagnostic use |
|---|---|
| /LOG/ALLLOG.LOG | Combines key, touch, alarm, PLC I/O, tool-offset change, workpiece-offset change and AC power ON/OFF histories. Useful for operating context; it is not a sampled waveform. |
| /LOGEX/ALLLOG1.LOG to ALLLOG3.LOG | All-history snapshots saved on servo/spindle alarms, up to three; 1 is the latest. S02 Initial parameter error does not trigger this backup, so a missing snapshot cannot rule out S02. |
| /LOGEX/ALM-SV1.LOG to ALM-SV5.LOG | Detailed servo/spindle alarm history; 1 is the latest. |
| /LOGEX/ALM-OTR1.LOG to ALM-OTR5.LOG | Detailed history of alarms other than servo/spindle alarms; 1 is the latest. Page 127 excludes warnings from detailed alarm history. |
These records have different scopes and retention counts. Do not expect every warning to have an ALM-SV file, or treat the five latest detailed records as the complete alarm history.
Exporting existing evidence when ALLLOG is not listed
- Following page 132, open Mainte → I/O. Set source device A to Memory and directory /LOG, displayed as History, then enter ALLLOG.LOG directly. The manual says refreshing the list still will not list this file; the same applies to KEYLOG.LOG and TOUCHLOG.LOG.
- Use Area change to select destination device B, directory and filename. Use supported, approved media and check space and existing filenames to avoid overwriting earlier evidence. The manual's HD destination is an example.
- Verify the direction Trnsfr A→B, then output the file. Check that a readable destination file was actually created and record the collection time and source machine. Existence alone does not prove the file covers the fault interval.
- For detailed alarm data, page 133 uses source directory /LOGEX and ALM-SVn.LOG or ALM-OTRn.LOG, with n from 1 to 5. These groups appear after List update. Do not apply the /LOG listing rule to every directory.
When interpreting ALLLOG, note #11052 LOG Sort Order on page 131: 0 outputs each history category separately in ascending time order; 1 merges all categories in ascending time order. Check the existing setting and actual file structure without changing the parameter for this analysis. Identical timestamps do not prove physically simultaneous events.
Hypothetical example and limits
Suppose a handover says only, “ALLLOG is absent from the list, and restarting did not produce new logs.” If the screenshot also shows History stop, examine the direct-filename export method and whether Stop or Data clear was used earlier as separate questions. Neither memory failure nor the absence of machine alarms follows from those observations. This is a hypothetical reasoning example, not a field repair or test result.
Evidence extraction does not replace safe stopping, isolation or the builder's maintenance procedure. Do not clear history, force NETSTP, write PLC signals or relax protections to obtain a “cleaner” log. Qualified personnel must address abnormal motion or alarms under the builder's instructions.
Source
M800/M80/E80 Series Maintenance Manual, IB-1501273-L, §§4.11–4.11.4: printed pages 127–128 (data types and states), 129–130 (start, stop and clear), 131 (file scope and sorting), 132–133 (export and viewing). Fields, paths and behavior come from the manufacturer's manual. The evidence-review workflow is editorial analysis; no machine testing was performed.