What the SRVO-105 alarm means

A safety fence door was opened or an emergency stop was activated while the system was in automatic mode. This is a fault we handle frequently on FANUC R-30iA / R-30iB / R-30iB Plus systems — in most cases we can pin down the root cause on the first site visit.

Most common causes

  • Operator opened the fence door
  • Door interlock switch misaligned or failing
  • E-stop button pressed or sticky
  • Wiring fault in the door switch circuit
Field note: The first item on this list is what we hit most often on real machines — clear that one before going deeper.

Step-by-step field fix

  1. Close the door and reset the E-stop, then press RESET
  2. If the alarm will not clear, test the door interlock switch for proper operation
  3. Check door switch alignment - vibration often shifts the actuator
  4. Inspect the safety circuit wiring for loose terminals
Safety first: For FANUC srvo-105, this alarm is the safety circuit itself: jumpering a door switch or forcing a contactor removes the protection entirely - no protective action when something happens, and no defensible account of responsibility. On site you may look at after confirming power-off the first step yourself: Close the door and reset the E-stop, then press RESET. Beyond that it is the e-stop chain and safety circuit work - leave it to a professional.

How we diagnose safety-chain faults on site

FANUC srvo-105 belongs to the safety chain & e-stop family. On FANUC srvo-105 the failing stage is Dual Check Safety (e-stop board plus dual-channel safety circuit) on the R-30iB Plus / R-30iB Mate Plus / R-30iA - continuity of one series loop: e-stop buttons, door switches, light curtains, safety relays and the enabling device. We start reading FANUC srvo-105 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-105 runs: e-stop / door / curtain -> safety relay (dual channel) -> controller safety input -> motor-off and brake apply.

FANUC srvo-105 is sometimes designed behaviour, not a fault - Releasing the enabling device (three-position switch) in manual mode triggers a protective stop by design, yet plenty of sites report it as an alarm. The switch enables only in the middle position; fully released or pushed through both open - and pushing through is the instinctive panic reaction, which is exactly what the designers used. Knowing that clears a good share of mysterious protective stops. The real fault is worn contacts inside the switch, showing up as poor contact in the middle position.

Field notes on this page cover FANUC srvo-105 (Door Open or E.Stop); written by the Henghuan repair team, updated 2026-10-01.

Blocked by this alarm? We can help you analyze it over the phone

Tell us the alarm code, the model and what the machine was doing when the alarm appeared. FANUC srvo-105 FANUC srvo-105 is an everyday diagnosis for our engineers, and remote diagnosis (phone or video) costs nothing.

Get a Free Remote Diagnosis See Repair Services

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

Related Safety Chain & E-Stop alarms

SRVO-201 — Panel E-Stop SRVO-202 — TP E-Stop SRVO-204 — External E-Stop (SVEMG Abnormal) SRVO-230 — Chain 1 (+24V) Abnormal SRVO-231 — Chain 2 (0V) Abnormal SRVO-232 — NTED Input Abnormal
Same family: this code belongs to the Safety chain & e-stop alarms family - the page collects all Safety chain & e-stop-family codes we have handled, with the common inspection order and spares.
Other brands: see our KUKA, ABB, Yaskawa and Universal Robots field-fix libraries — or the full 10-brand hub.

Frequently asked questions

QWhat does the FANUC srvo-105 alarm mean?

A safety fence door was opened or an emergency stop was activated while the system was in automatic mode. This is a fault we handle frequently on FANUC R-30iA / R-30iB / R-30iB Plus systems — in most cases we can pin down the root cause on the first site visit. FANUC srvo-105 sits in the safety chain & e-stop family; on our work orders the highest-frequency trigger for this code is "Operator opened the fence door".

QCan I clear a FANUC srvo-105 alarm myself?

Whether FANUC srvo-105 clears on its own depends on the outcome of "Close the door and reset the E-stop, then press RESET". Finish the flow with "Inspect the safety circuit wiring for loose terminals" to confirm FANUC srvo-105 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-105 is "Door interlock switch misaligned or failing". Two attempts and still there means stop: FANUC srvo-105 involves the e-stop chain and safety circuit, and running FANUC srvo-105 on can turn a repairable fault into a replacement.

QA safety-chain fault like FANUC srvo-105 stops the line - how fast can you be here?

The commonest causes we see on FANUC srvo-105 are "Operator opened the fence door, Door interlock switch misaligned or failing, E-stop button pressed or sticky", so we stock the van against those. For FANUC srvo-105 specifically, we stock along the loop: safety relays, common door switches, e-stop buttons, light-curtain pairs and terminal blocks. For FANUC srvo-105, a safety-chain fault stops the whole line, so we rank it top priority and pre-triage by phone: door switch, e-stop or relay. Before we roll, tell us what FANUC srvo-105 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-105 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.