What the SRVO-062 alarm means
The absolute position data of the pulse coder was lost. The robot no longer knows where its axes are, so it cannot run in automatic mode until mastering is restored. This is one of the most common faults in our repair logs for the FANUC R-30iA / R-30iB / R-30iB Plus platform, and the first inspection typically locates the cause.
Most common causes
- Dead or disconnected backup battery in the robot base (most common)
- Pulse coder or motor was replaced
- Encoder cable was disconnected while power was off
- First power-up after long storage
Step-by-step field fix
- Check/replace the battery pack in the robot base (replace with controller power ON to avoid data loss on other axes)
- Power on, open the mastering screen and set $MASTER_ENB = 1
- Press RES_1PA (reset pulse coder alarm) and cycle power
- Perform zero position mastering (or quick mastering if a reference was saved), then calibrate
- Jog each axis slowly and verify zero marks line up before running production
How we diagnose calibration alarms on site
FANUC srvo-062 belongs to the battery & mastering family. On FANUC srvo-062 the failing stage is absolute encoders inside alpha-i motors, position memory held by the encoder battery pack on the R-30iB Plus / R-30iB Mate Plus / R-30iA - low battery voltage losing the absolute position memory, which then demands a fresh zero master - two jobs in one. We start reading FANUC srvo-062 at the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code.
The chain involved in FANUC srvo-062 runs: battery pack supply -> absolute position count -> memory held across power-off -> voltage too low loses it -> re-master required.
After mastering for FANUC srvo-062, verification is mandatory: Mastering must be verified, not celebrated. We run repeat-positioning on a fixed reference and spot-check the customer's live production points. If points are visibly off, the mastering datum is suspect, or a mechanical zero mark has shifted - for example after a reducer was replaced. In that case the datum is re-established rather than the master repeated. The master record, including per-axis values and verification results, is handed over in writing.
Field notes on this page cover FANUC srvo-062 (BZAL Alarm (Group / Axis)); written by the Henghuan repair team, updated 2026-10-01.
Real Field Case
Machine: FANUC R-2000iB/165F (2017)
Symptom: A customer's 2017 R-2000iB/165F sat idle over the weekend; on Monday every axis raised SRVO-062 (BZAL) — all absolute position data lost.
What we did: We measured each axis encoder battery below 2.8V, replaced the battery packs axis by axis, then ran full mastering against the calibration marks.
Result: After mastering all axis marks aligned and repeatability re-checked within ±0.05mm; welding production resumed the same day. Total about 4 hours.
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Related Battery & Mastering alarms
SRVO-065 — BLAL Alarm - Battery Voltage Low SRVO-075 — Pulse Position Mismatch SRVO-027 — Robot Not Mastered SRVO-038 — Pulse Mismatch (Group / Axis)Frequently asked questions
QWhat does the FANUC srvo-062 alarm mean?
The absolute position data of the pulse coder was lost. The robot no longer knows where its axes are, so it cannot run in automatic mode until mastering is restored. This is one of the most common faults in our repair logs for the FANUC R-30iA / R-30iB / R-30iB Plus platform, and the first inspection typically locates the cause. FANUC srvo-062 sits in the battery & mastering family; on our work orders the highest-frequency trigger for this code is "Dead or disconnected backup battery in the robot base (most common)".
QCan I clear a FANUC srvo-062 alarm myself?
Whether FANUC srvo-062 clears on its own depends on the outcome of "Check/replace the battery pack in the robot base (replace with controller power ON to avoid data loss on other axes)". Finish the flow with "Jog each axis slowly and verify zero marks line up before running production" to confirm FANUC srvo-062 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-062 is "Pulse coder or motor was replaced". Two attempts and still there means stop: FANUC srvo-062 involves battery polarity and zero data, and running FANUC srvo-062 on can turn a repairable fault into a replacement.
QWhen you handle FANUC srvo-062, will my programs and frames get lost?
The commonest causes we see on FANUC srvo-062 are "Dead or disconnected backup battery in the robot base (most common), Pulse coder or motor was replaced, Encoder cable was disconnected while power was off", so we stock the van against those. For FANUC srvo-062 specifically, we carry the model's battery pack and mastering fixtures; battery changes belong in scheduled maintenance, not in alarm response. For FANUC srvo-062, on battery and mastering alarms we back up programs and points first, master second and verify precision on site. Before we roll, tell us what FANUC srvo-062 shows on the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code and what the machine was doing - phone or video triage is free.
This page on FANUC srvo-062 is based on the field experience of the Henghuan Robotics repair team. Alarm explanations are our own summary for troubleshooting reference and may differ across controller and software versions — if unsure, verify against FANUC documentation or reach out to us. Henghuan is an independent service provider with no affiliation or endorsement by FANUC.