What the SRVO-201 alarm means

The emergency stop button on the operator panel is pressed, or its circuit is abnormal. We are very familiar with this alarm on FANUC R-30iA / R-30iB / R-30iB Plus systems — usually the first on-site inspection is enough to confirm the cause.

Most common causes

  • Button pressed
  • Button contact failure or sticky mechanism
  • Wiring fault in the panel E-stop loop
Field note: Our ticket data shows the first cause is by far the most common — start there to avoid dead ends.

Step-by-step field fix

  1. Twist-release the E-stop button and press RESET
  2. If it will not reset, check the button contacts with a multimeter (both channels)
  3. Inspect the wiring from panel to E-stop board
Safety first: For FANUC srvo-201, 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. The self-serviceable action is Twist-release the E-stop button and press RESET; anything past that falls under the e-stop chain and safety circuit and needs a certified engineer.

How we diagnose safety-chain faults on site

FANUC srvo-201 belongs to the safety chain & e-stop family. On FANUC srvo-201 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-201 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-201 runs: e-stop / door / curtain -> safety relay (dual channel) -> controller safety input -> motor-off and brake apply.

FANUC srvo-201 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-201 (Panel 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-201 FANUC srvo-201 is an everyday diagnosis for our engineers, and remote diagnosis (phone or video) costs nothing.

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Related Safety Chain & E-Stop alarms

SRVO-105 — Door Open or 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-201 alarm mean?

The emergency stop button on the operator panel is pressed, or its circuit is abnormal. We are very familiar with this alarm on FANUC R-30iA / R-30iB / R-30iB Plus systems — usually the first on-site inspection is enough to confirm the cause. FANUC srvo-201 sits in the safety chain & e-stop family; on our work orders the highest-frequency trigger for this code is "Button pressed".

QCan I clear a FANUC srvo-201 alarm myself?

Whether FANUC srvo-201 clears on its own depends on the outcome of "Twist-release the E-stop button and press RESET". Finish the flow with "Inspect the wiring from panel to E-stop board" to confirm FANUC srvo-201 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-201 is "Button contact failure or sticky mechanism". Do not chase takt through a repeating FANUC srvo-201. Left alone, safety chain & e-stop faults tend to graduate from repairable to must-replace.

QA safety-chain fault like FANUC srvo-201 stops the line - how fast can you be here?

The commonest causes we see on FANUC srvo-201 are "Button pressed, Button contact failure or sticky mechanism, Wiring fault in the panel E-stop loop", so we stock the van against those. For FANUC srvo-201 specifically, we stock along the loop: safety relays, common door switches, e-stop buttons, light-curtain pairs and terminal blocks. For FANUC srvo-201, 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-201 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-201 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.