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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.

EEF1

Control EEPROM Error

Schneider Electric · Altivar Machine ATV320 Variable Speed Drive

What does EEF1 mean?

A detected error within the Control EEPROM. This non-volatile memory stores critical drive parameters and firmware. Corruption here can prevent the drive from booting, operating, or retaining its configuration, leading to a complete system failure.

Common Causes

  • Data corruption within the EEPROM due to power disturbances (e.g., voltage spikes, brownouts, unstable supply).
  • Failed EEPROM chip on the control board, preventing reliable read/write operations of stored parameters.
  • Firmware update process interrupted or failed, leaving the EEPROM in an inconsistent or partially written state.
  • Electrostatic discharge (ESD) damage to the control board during handling or maintenance activities.
  • Over-temperature condition in the drive's control section, leading to component stress and memory degradation.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Power cycle the drive. If the fault persists, attempt a factory reset (e.g., set Parameter P0-01 = 2) to re-initialize EEPROM content.

  2. 2

    2. Re-load a known-good configuration file via the drive's communication port to overwrite potentially corrupted data.

  3. 3

    3. Verify the stability of the drive's internal control power supply (e.g., 24VDC rail) using a multimeter.

  4. 4

    4. Check the drive's ambient operating temperature and ensure cooling fans are functioning correctly (e.g., fan current, airflow).

  5. 5

    5. If persistent, consider replacing the control board as the EEPROM chip may be physically damaged or worn out.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

ASFAngle ErrorCFFIncorrect ConfigurationCFI2Configuration Transfer Error
Source: Schneider Electric Altivar Machine ATV320 Variable Speed Drive
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