FANUC 0i-F APZ loss: interpreting the cause records in diagnosis 310/311
Preserve diagnosis 310/311 before investigating APZ=0. Distinguish parameter changes from battery or counting events in built-in and separate detectors, without treating retained bits as current faults or a timeline.
Contents
Finding parameter 1815#4 (APZ) at 0 on an axis does not justify diagnosing a depleted battery from “lost reference” alone. More useful questions are which cause the control recorded, which detector it concerns, and what operations preceded the finding. Diagnosis 310/311 helps narrow the investigation when read alongside current alarms, parameter differences and maintenance records.
Scope and retention of the records
This article uses the FANUC Series 0i-MODEL F Maintenance Manual B-64605EN/01, §1.3.2, printed pp. 19–20. It is limited to the covered 0i-TF, 0i-MF and 0i-PF models and their supported configurations. Do not transfer these definitions directly to 0i-F Plus, earlier generations or other revisions.
The manual identifies 310/311 as records of causes that set APZ to 0. Once a cause bit is set, it remains set until the corresponding axis’s absolute position detector zero point is established again. A 1 may therefore describe an earlier event rather than a fault still present. These items do not provide event times or sequencing. Preserve them before qualified personnel separately address reference-position recovery; do not reset the zero point merely to clear the records.
Six useful diagnostic clues
The table selects easily misinterpreted bits, not the complete 310/311 definitions. “Further evidence” contains our diagnostic suggestions, not manufacturer-prescribed repair steps. Interpret any other set bits using the same manual revision.
| Diagnosis bit | Manufacturer’s definition, summarized | Further evidence |
|---|---|---|
| 310#0 PR1 | A parameter in the specified list changed; 1850 is one example. | Compare this machine’s before-and-after parameters and operation records. The bit does not identify which parameter changed. |
| 311#2 AL3 | The built-in serial Pulsecoder detected 0 V battery voltage. | Confirm the axis feedback configuration and battery-maintenance records. This is not a report that the voltage measures 0 V now. |
| 311#5 XBZ | A separate serial position detector encountered battery 0 V or SV0382, a counting error. | Use the full alarm and detector identity to distinguish the two causes represented by this bit. |
| 311#3 AL4 | SV0367, a built-in detector counting error, was detected. | Check the matching alarm and circumstances; this bit alone does not establish a battery fault. |
| 311#1 AL2 | With 1819#1 (CRF)=1, SV0445, SV0447 or SV0646 was detected. | Record CRF and the full alarm together. Retain this configuration condition; do not change CRF to test it. |
| 311#6 DUA | With CRF=1, SV0421, excessive semi-closed/full-closed position error, was detected. | Preserve the relationship between the two feedback systems and the alarm record rather than reducing this to a battery warning. |
AL3 and XBZ concern different detectors and should not be grouped simply because both mention batteries. XBZ also covers a counting-error branch, so XBZ=1 is insufficient grounds for replacing a battery. PR1 points toward parameter-change evidence. Locate applicable original parameters, the actual change and its timing before assessing its relevance to the present problem.
Reconstruct this machine’s sequence of events
- Preserve the original screens.Record machine ID, CNC model and software revision, path and axis name, APZ, 310, 311, full alarms and capture time. Keep all eight bits and their displayed order; do not combine rows from different axes.
- Identify the feedback configuration.Use this machine’s configuration and drawings to distinguish the built-in motor detector from a separate position detector. Mark unknowns as unconfirmed rather than inferring the entire hardware arrangement from one set bit.
- Find completed changes.List battery work, feedback-component replacement, parameter restoration or editing, and the latest reference-position setting separately. Compare existing machine-specific records offline first; do not repeat those operations to reproduce a cause bit.
- Separate findings from gaps.“AL3 recorded; battery-circuit condition awaiting inspection” is more accurate than “battery failed.” “PR1 recorded; earlier parameters unavailable” is more useful than restoring an arbitrary similar machine’s parameter set.
When present settings and historical records differ, label their dates. Seeing CRF=1 now cannot reconstruct every setting at the alarm time. Also record any subsequent zero-point setting: 310/311 read after that intervention cannot substitute for the earlier record. If diagnosis cannot be read, document the missing evidence instead of filling it with assumptions.
Hypothetical example: PR1 and AL3 together
Suppose one axis of an applicable machine shows APZ=0. Read from #7 to #0, diagnosis 310 is 00000001 and 311 is 00000100. These decode as PR1=1 and AL3=1. These are hypothetical values illustrating the reasoning, not a repair case.
The control has retained two categories of cause: a listed parameter change and a built-in serial Pulsecoder battery-zero event. Their order is unknown. It would be unjustified to conclude that power loss erased the reference and someone then changed parameters. Seek parameter differences, battery-work records and the latest zero-point-setting time. If only one event is corroborated, leave the other open; simultaneous set bits do not establish a complete causal sequence.
Separate cause identification from recovery acceptance
This article stops at read-only evidence gathering. Do not alter APZ or CRF, unplug feedback, disconnect batteries or force axis movement as an experiment. Electrical inspection, re-establishing absolute position, and acceptance checks of reference position and machine travel belong to qualified personnel following the machine builder’s procedure. Cause records guide investigation; they cannot replace physical-position verification or authorize resumed machining merely because an alarm disappears.
Source
FANUC Series 0i-MODEL F Maintenance Manual B-64605EN/01: §1.3.2, printed pp. 19–20, APZ-clearing causes and diagnosis 310/311; applicable models in preface p-2. This is a third-party public mirror of a FANUC-authored manual, not an official FANUC download site. The evidence-organizing method and hypothetical example are editorial analysis, with no machine testing performed.