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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

EF0

Opt External Flt

Yaskawa · E7 Drive

What does EF0 mean?

An external fault condition exists, originating from the communication option card. This suggests an issue with an external device or signal connected via the option card, potentially leading to incorrect drive operation. This can also appear as a flashing alarm.

Common Causes

  • An external safety device (e.g., E-stop, limit switch) connected to the option card has tripped or changed state.
  • Broken or damaged wiring between the communication option card and the external fault source.
  • Incorrect configuration of the digital input on the option card (e.g., normally open vs. normally closed logic).
  • Loss of auxiliary power to the external device providing the fault signal to the option card.
  • Communication timeout or error from the master controller (e.g., PLC) to the drive's option card.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Verify the status of all external devices connected to the option card's fault input terminals.

  2. 2

    2. Using a multimeter, test continuity of wiring from the option card's fault input terminals to the external fault source.

  3. 3

    3. Confirm the correct parameter settings for the option card's fault input logic and assignment (e.g., input type, debounce time).

  4. 4

    4. Check diagnostic LEDs on the option card (if available) for specific indications of external fault status.

  5. 5

    5. Temporarily disconnect the external fault signal from the option card's input to determine if the fault is external or internal.

Browse all codes in this manual (64)
Verified technical data. Last updated: April 2026

Related Faults

BUSOption Communication ErrorCALLSI-F/G ComCallCEModbus Communication Error
Source: Yaskawa E7 Drive
View Official PDFSearch more codes in this manual