What the 9711 alarm means

The controller cannot communicate with the serial encoder; position feedback for the axis is lost. We see this alarm constantly when servicing Epson RC90 / RC700 (EPSON RC+) systems, and the first on-site pass usually pins down the cause.

Most common causes

  • Damaged encoder signal cable
  • Loose connection at motor or DMB
  • Failed encoder or encoder I/F board
  • Noise on the encoder line
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. Reboot the controller once
  2. Check the motor, DMB and encoder I/F board connections
  3. Check the signal cable continuity
  4. Verify robot configuration matches the hardware
  5. Replace the DMB and/or encoder I/F board if communication still fails
Safety first: For EPSON 9711, 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. On site you may look at after confirming power-off the first step yourself: Reboot the controller once. Beyond that it is position feedback and brake release work - leave it to a professional.

How we diagnose encoder alarms on site

EPSON 9711 belongs to the encoder & position family. On EPSON 9711 the failing stage is encoder and origin data, absolute position held by battery on the RC700-A / RC90-B and the RC series - the feedback path: encoder body, encoder cable, battery, measuring board and the stored position memory. We start reading EPSON 9711 at the EPSON RC+ error list and controller front-panel indicators; codes segment as 4xxx / 5xxx / 9xxx.

The chain involved in EPSON 9711 runs: motor-side encoder -> encoder cable -> drive / measuring board acquisition -> position count and zero data -> battery-held memory.

On EPSON 9711 the commonest field report is Damaged encoder signal cable; 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 EPSON 9711 (Serial Encoder Communication Failure); written by the Henghuan repair team, updated 2026-10-01.

Still unresolved? Our engineers are standing by

Just tell us the alarm code, the robot model and which program was running, and our engineers will help you narrow it down — phone and video remote diagnosis are both free.

Get a Free Remote Diagnosis See Repair Services

Hotline: +86-20-39029800 · WhatsApp: +86-188-1886-2860

Related Encoder & Position alarms

5098 — High Temperature of Encoder 9716 — Power Supply Failure of Absolute Encoder 9718 — Absolute Encoder Battery Alarm
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 Nachi · Omron · ESTUN and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the EPSON 9711 alarm mean?

The controller cannot communicate with the serial encoder; position feedback for the axis is lost. We see this alarm constantly when servicing Epson RC90 / RC700 (EPSON RC+) systems, and the first on-site pass usually pins down the cause. EPSON 9711 sits in the encoder & position family; on our work orders the highest-frequency trigger for this code is "Damaged encoder signal cable".

QCan I clear a EPSON 9711 alarm myself?

Whether EPSON 9711 clears on its own depends on the outcome of "Reboot the controller once". Finish the flow with "Replace the DMB and/or encoder I/F board if communication still fails" to confirm EPSON 9711 - do not skip it. If that step is clean, the second most frequent cause on EPSON 9711 is "Loose connection at motor or DMB". Two attempts and still there means stop: EPSON 9711 involves position feedback and brake release, and running EPSON 9711 on can turn a repairable fault into a replacement.

QFor encoder alarms like EPSON 9711, can it be fixed in one visit?

The commonest causes we see on EPSON 9711 are "Damaged encoder signal cable, Loose connection at motor or DMB, Failed encoder or encoder I/F board", so we stock the van against those. For EPSON 9711 specifically, we carry feedback-path parts: encoder cables, battery packs, connector pins and the measuring-board type data for the brand. For EPSON 9711, 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 EPSON 9711 shows on the EPSON RC+ error list and controller front-panel indicators; codes segment as 4xxx / 5xxx / 9xxx and what the machine was doing - phone or video triage is free.

The notes on EPSON 9711 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 Epson documentation or contact us with questions. Henghuan is an independent service provider, not affiliated with or endorsed by Epson.