What the 1001 alarm means

After a safety-related stop, KSS requires the operator to acknowledge the operator-safety message before the drives can be re-enabled — the robot will not move until the acknowledgment button is pressed and held for the configured time. This is one of the faults our repair team handles on KUKA KRC2 / KRC4 / KRC5 (KSS) systems — the cause is usually identifiable within the first on-site inspection.

Most common causes

  • E-stop or safety door released but the acknowledgment button never pressed
  • Acknowledgment button pressed too briefly (default hold time is about 1 s)
  • Faulty or miswired operator-safety acknowledgment input on the X11 safety interface
  • Safety configuration expecting the acknowledgment from a different device (SmartPad vs. external button)
Field note: the first item on this list is what we find most often on real machines. Check it before you go deeper.

Step-by-step field fix

  1. Confirm every E-stop is released and all safety doors are closed
  2. Press and HOLD the operator-safety acknowledgment button until the SmartHMI message clears
  3. Open Diagnosis → Message Log on the SmartPad and clear any remaining pending messages
  4. If the message returns immediately, verify the X11 acknowledgment wiring and the safety configuration in WorkVisual
  5. Power-cycle the controller once if the acknowledgment state appears latched in error
Safety first: never bypass safety circuits or force contactors closed. If the alarm involves E-stop chains, brakes or drive power, and you are not a trained robot technician, contact a professional — wrong moves here can cost you a robot or an injury.

Still stuck? Get an engineer on the phone — right now

Tell us the alarm code, the robot model and what was happening when the alarm came up. Our engineers run these diagnostics every day, and remote diagnosis by phone or video call is free.

Get a Free Remote Diagnosis See Repair Services

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

Related Safety Chain & E-Stop alarms

1002 — Drives-On Not Asserted ($DRIVES_ON) 1010 — Move Enable Missing — E-Stop or Safety Relay Open 15074 — Safety Junction Error in Drive — Channel N
Other brands: we also keep field-fix libraries for ABB · Yaskawa · Universal Robots and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the KUKA 1001 alarm mean?

After a safety-related stop, KSS requires the operator to acknowledge the operator-safety message before the drives can be re-enabled — the robot will not move until the acknowledgment button is pressed and held for the configured time. In field practice it belongs to the safety chain & e-stop family of faults.

QCan I clear a KUKA 1001 alarm myself?

Sometimes. Work through the step-by-step checks on this page — the first listed cause is what we find most often in the field. If the alarm returns after two attempts, or the fault involves power, brakes or safety circuits, stop and call a qualified robot service engineer.

QHow fast can a Henghuan engineer help?

On-site response in the Pearl River Delta within 30 minutes to 3 hours, across mainland China in 1-3 business days, and worldwide within 2-5 business days. Remote diagnosis by phone/WhatsApp/video is available immediately.

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 KUKA documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by KUKA.