What the E# (-1025) alarm means

The servo system detected an encoder fault on the indicated joint; position feedback cannot be trusted and the joint will not move. We see this alarm constantly when servicing Omron SmartController (ACE / Viper / Cobra) systems, and the first on-site pass usually pins down the cause.

Most common causes

  • Encoder backup battery dead (absolute position lost)
  • Damaged encoder cable at a flex point
  • Failing encoder
  • Noise on the encoder signal
Field note: Based on our handling experience the first cause is the most frequent — use it as your starting point.

Step-by-step field fix

  1. Replace the encoder backup battery pack (see the robot user guide for location)
  2. Inspect the encoder cable along the arm flex path
  3. Clear the fault with the service utility (e.g. RSC_SET on Adept/Omron systems) if position data was lost
  4. Re-calibrate the joint against its mechanical reference
  5. Replace the encoder if faults return
Safety first: For OMRON e-1025, encoder alarms often mean position data cannot be trusted: actual pose may disagree with the system record, so releasing a brake or jogging carries unexpected-motion risk. The self-serviceable action is Replace the encoder backup battery pack (see the robot user guide for location); anything past that falls under position feedback and brake release and needs a certified engineer.

How we diagnose encoder alarms on site

OMRON e-1025 belongs to the encoder & position family. On OMRON e-1025 the failing stage is motor-integrated encoders; temperature and feedback faults raise high-temp / encoder messages on the OMRON robot controllers (including SCARA and cobot companions) - the feedback path: encoder body, encoder cable, battery, measuring board and the stored position memory. We start reading OMRON e-1025 at controller status indicators and the software error list (letter prefixes RC / SW / V / M / D / A / E).

The chain involved in OMRON e-1025 runs: motor-side encoder -> encoder cable -> drive / measuring board acquisition -> position count and zero data -> battery-held memory.

On OMRON e-1025 the commonest field report is Encoder backup battery dead (absolute position lost); the highest-share cause is plain: The highest-share cause in this family is unglamorous: battery voltage. Absolute encoders hold the position count on a battery while power is off; below threshold the memory is gone and the controller demands a fresh master. Packs are designed for roughly two to three years, but a hot cabinet shortens that a lot. We carry spare packs, and after a swap we master immediately and re-check every axis zero so the customer does not run on an offset.

Field notes on this page cover OMRON e-1025 (Encoder Fault (Joint N)); written by the Henghuan repair team, updated 2026-10-01.

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Related Encoder & Position alarms

H# — High Temperature — Encoder (Joint N)
Same family: this code belongs to the Encoder & position alarms family - the page collects all Encoder & position-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for ESTUN · INOVANCE · EFORT and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the OMRON e-1025 alarm mean?

The servo system detected an encoder fault on the indicated joint; position feedback cannot be trusted and the joint will not move. We see this alarm constantly when servicing Omron SmartController (ACE / Viper / Cobra) systems, and the first on-site pass usually pins down the cause. OMRON e-1025 sits in the encoder & position family; on our work orders the highest-frequency trigger for this code is "Encoder backup battery dead (absolute position lost)".

QCan I clear a OMRON e-1025 alarm myself?

Whether OMRON e-1025 clears on its own depends on the outcome of "Replace the encoder backup battery pack (see the robot user guide for location)". Finish the flow with "Replace the encoder if faults return" to confirm OMRON e-1025 - do not skip it. If that step is clean, the second most frequent cause on OMRON e-1025 is "Damaged encoder cable at a flex point". Do not chase takt through a repeating OMRON e-1025. Left alone, encoder & position faults tend to graduate from repairable to must-replace.

QFor encoder alarms like OMRON e-1025, can it be fixed in one visit?

The commonest causes we see on OMRON e-1025 are "Encoder backup battery dead (absolute position lost), Damaged encoder cable at a flex point, Failing encoder", so we stock the van against those. For OMRON e-1025 specifically, we carry feedback-path parts: encoder cables, battery packs, connector pins and the measuring-board type data for the brand. For OMRON e-1025, encoder alarms are mostly broken cores and dead batteries, both of which ride in the van, so most clear in one visit. Before we roll, tell us what OMRON e-1025 shows on controller status indicators and the software error list (letter prefixes RC / SW / V / M / D / A / E) and what the machine was doing - phone or video triage is free.

The notes on OMRON e-1025 were summarized by the Henghuan Robotics repair team from on-site service. The alarm interpretation is our empirical summary for troubleshooting reference and may vary by controller and software version — please check Omron documentation or contact us with questions. Henghuan is an independent service provider, not affiliated with or endorsed by Omron.