What the SRVO-230 alarm means

The +24V side of the dual-channel emergency stop chain circuit is abnormal. The two safety channels no longer agree, so the controller cuts servo power. Our engineers run into this alarm every week on FANUC R-30iA / R-30iB / R-30iB Plus controllers, and a single on-site inspection usually identifies the problem.

Most common causes

  • One channel of an E-stop/door switch contact failed or is wired to only one channel
  • Wiring break or loose terminal in chain 1
  • E-stop board or panel board failure
  • Slow/bounced contacts exceeding the chain mismatch time
Field note: In our repair stats the first cause has the highest hit rate, so confirm it first before digging further.

Step-by-step field fix

  1. Do NOT bypass the safety circuit - find the real fault
  2. Check every device in the chain (E-stops, door switches, deadman, external inputs) with a multimeter, both channels
  3. Look for oxidized or loose connectors - vibration-prone installations fail here
  4. If wiring is clean, suspect the E-stop board in the controller
Safety first: For FANUC srvo-230, 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: Do NOT bypass the safety circuit - find the real fault. 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-230 belongs to the safety chain & e-stop family. On FANUC srvo-230 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-230 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-230 runs: e-stop / door / curtain -> safety relay (dual channel) -> controller safety input -> motor-off and brake apply.

FANUC srvo-230 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-230 (Chain 1 (+24V) Abnormal); written by the Henghuan repair team, updated 2026-10-01.

Real Field Case

Machine: FANUC R-30iB system (2018)

Symptom: A line robot repeatedly raised SRVO-230 (safety chain 1 fault), tripping again minutes after each reset.

What we did: We traced the safety chain segment by segment with a multimeter and found one door-switch contact oxidized with high contact resistance; we replaced the door switch and cleaned the terminals.

Result: No recurrence for a full week after the fix — the intermittent stoppage was resolved.

No luck? Hand it to the team that fixes this daily

Share the alarm code, machine model and the operating condition at the moment of the alarm. Our engineers are highly experienced with FANUC srvo-230, and remote diagnosis (phone/video) is completely free.

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Related Safety Chain & E-Stop alarms

SRVO-105 — Door Open or E.Stop SRVO-201 — Panel E-Stop SRVO-202 — TP E-Stop SRVO-204 — External E-Stop (SVEMG 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-230 alarm mean?

The +24V side of the dual-channel emergency stop chain circuit is abnormal. The two safety channels no longer agree, so the controller cuts servo power. Our engineers run into this alarm every week on FANUC R-30iA / R-30iB / R-30iB Plus controllers, and a single on-site inspection usually identifies the problem. FANUC srvo-230 sits in the safety chain & e-stop family; on our work orders the highest-frequency trigger for this code is "One channel of an E-stop/door switch contact failed or is wired to only one channel".

QCan I clear a FANUC srvo-230 alarm myself?

Whether FANUC srvo-230 clears on its own depends on the outcome of "Do NOT bypass the safety circuit - find the real fault". Finish the flow with "If wiring is clean, suspect the E-stop board in the controller" to confirm FANUC srvo-230 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-230 is "Wiring break or loose terminal in chain 1". Do not chase takt through a repeating FANUC srvo-230. Left alone, safety chain & e-stop faults tend to graduate from repairable to must-replace.

QA safety-chain fault like FANUC srvo-230 stops the line - how fast can you be here?

The commonest causes we see on FANUC srvo-230 are "One channel of an E-stop/door switch contact failed or is wired to only one channel, Wiring break or loose terminal in chain 1, E-stop board or panel board failure", so we stock the van against those. For FANUC srvo-230 specifically, we stock along the loop: safety relays, common door switches, e-stop buttons, light-curtain pairs and terminal blocks. For FANUC srvo-230, 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-230 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-230 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 FANUC documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by FANUC.