PF Comm Err

Internal Communication Error

Omron · SXF Inverter

What does PF Comm Err mean?

This fault indicates an internal communication error within the variable speed drive. This means critical components or modules within the VSD are unable to communicate properly, often pointing to a hardware fault or corrupted firmware. This can prevent the drive from functioning, lead to unpredictable behavior, or cause a complete drive shutdown, requiring expert diagnosis.

Common Causes

  • Loose or corroded ribbon cable connections between internal control boards (e.g., CPU, I/O, power board).
  • Electromagnetic Interference (EMI) disrupting internal communication buses, especially in noisy environments.
  • Failed communication chip or transceiver on a control board.
  • Hardware malfunction on the main control board (CPU).
  • Corrupted firmware or configuration settings causing communication conflicts.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power down and disconnect drive. Carefully inspect and reseat all internal ribbon cables and connectors.

  2. 2

    Verify proper grounding of the drive and motor shield.

  3. 3

    Check for external sources of high EMI near the drive (e.g., unshielded power cables, welding equipment).

  4. 4

    Perform a firmware update (if available and recommended by manufacturer) or factory reset (e.g., P9-02 = 1).

  5. 5

    Inspect control boards for visible damage, burnt components, or liquid ingress.

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Verified technical data. Last updated: March 2026

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