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ErrorLib — Industrial Fault Code Library

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5126

Option in slot C1: Hardware incompatible with control board

Danfoss · VLT AutomationDrive FC 301/302

What does 5126 mean?

The hardware of the option card installed in slot C1 is incompatible with the control board hardware. This prevents proper integration and function of the option, requiring a compatible replacement.

Common Causes

  • Option card firmware version incompatible with the control board firmware version.
  • Incorrect option card type installed in slot C1 (e.g., I/O card installed when a fieldbus card is required).
  • Physical damage to the option card's connector pins preventing proper electrical contact with slot C1.
  • Control board hardware revision (e.g., MCB101 Rev 2.0) is not supported by the installed option card.
  • Corrupted data or failed initialization sequence of the option card during drive power-up.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power down the drive and remove the option card from slot C1.

  2. 2

    Verify the option card's part number against the drive's compatibility matrix in the technical documentation.

  3. 3

    Check the option card's connector pins and the control board's slot C1 header for physical damage or bent pins.

  4. 4

    Install a known compatible option card with the correct part number and firmware version.

  5. 5

    Power up the drive and verify the fault clears and the option card is recognized in parameter 15-00 (Option Card Detected).

Browse all codes in this manual (66)
Verified technical data. Last updated: April 2026

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Source: Danfoss VLT AutomationDrive FC 301/302
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