What the Er.102 alarm means

The drive cannot communicate with the motor encoder; position feedback is lost and the axis is disabled. We see this alarm constantly when servicing INOVANCE IRCB500 / IRCB501 + SV660 servo systems, and the first on-site pass usually pins down the cause.

Most common causes

  • Encoder cable broken inside the cable chain
  • Connector pins oxidized or backed out
  • Noise on the encoder line from poor shielding
  • Encoder or drive interface circuit failure
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. Reseat the encoder connectors at both ends
  2. Continuity-test the cable through the full motion of the cable chain
  3. Check shield termination and separation from power cables
  4. Swap-test with a known-good cable
  5. Replace encoder (motor) or drive based on swap results
Safety first: For INOVANCE er-102, 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 Reseat the encoder connectors at both ends; anything past that falls under position feedback and brake release and needs a certified engineer.

How we diagnose encoder alarms on site

INOVANCE er-102 belongs to the encoder & position family. On INOVANCE er-102 the failing stage is absolute encoders with battery (ER.740 / ER.831 class point at encoder and battery) on the Inovance robot controllers (IRCB series and kin) - the feedback path: encoder body, encoder cable, battery, measuring board and the stored position memory. We start reading INOVANCE er-102 at the pendant alarm screen (ER.xxx / 0x9xxx segments) and the servo panel Er code.

The chain involved in INOVANCE er-102 runs: motor-side encoder -> encoder cable -> drive / measuring board acquisition -> position count and zero data -> battery-held memory.

If Encoder cable broken inside the cable chain on INOVANCE er-102 comes and goes, suspect interference: Encoder feedback is a low-level signal and interference-sensitive. Position data jumping now and then, alarms appearing and disappearing, usually means the shield is not landed properly or the encoder cable shares a drag chain with power cables. We check that the shield lands single-ended at the cabinet, that routing is separated in the chain, and that connector pins are not oxidised. A surprising number of these clear after re-routing, and swapping the encoder would have been money wasted.

Field notes on this page cover INOVANCE er-102 (Encoder Communication Fault); written by the Henghuan repair team, updated 2026-10-01.

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Related Encoder & Position alarms

Er.740 — Encoder Signal Interference / Count Error Er.831 — Absolute Encoder Battery Low
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 EFORT · JAKA · AUBO and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the INOVANCE er-102 alarm mean?

The drive cannot communicate with the motor encoder; position feedback is lost and the axis is disabled. We see this alarm constantly when servicing INOVANCE IRCB500 / IRCB501 + SV660 servo systems, and the first on-site pass usually pins down the cause. INOVANCE er-102 sits in the encoder & position family; on our work orders the highest-frequency trigger for this code is "Encoder cable broken inside the cable chain".

QCan I clear a INOVANCE er-102 alarm myself?

Whether INOVANCE er-102 clears on its own depends on the outcome of "Reseat the encoder connectors at both ends". Finish the flow with "Replace encoder (motor) or drive based on swap results" to confirm INOVANCE er-102 - do not skip it. If that step is clean, the second most frequent cause on INOVANCE er-102 is "Connector pins oxidized or backed out". When INOVANCE er-102 keeps coming back it is not a one-off trigger - especially if Replace encoder (motor) or drive based on swap results is where you get stuck. Do not keep producing through INOVANCE er-102.

QFor encoder alarms like INOVANCE er-102, can it be fixed in one visit?

The commonest causes we see on INOVANCE er-102 are "Encoder cable broken inside the cable chain, Connector pins oxidized or backed out, Noise on the encoder line from poor shielding", so we stock the van against those. For INOVANCE er-102 specifically, we carry feedback-path parts: encoder cables, battery packs, connector pins and the measuring-board type data for the brand. For INOVANCE er-102, 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 INOVANCE er-102 shows on the pendant alarm screen (ER.xxx / 0x9xxx segments) and the servo panel Er code and what the machine was doing - phone or video triage is free.

This page on INOVANCE er-102 was written by the Henghuan Robotics repair team from field service experience. Alarm descriptions are our own summary for troubleshooting reference and may vary by controller and software version — when in doubt, check your INOVANCE documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by INOVANCE.