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ErrorLib — Industrial Fault Code Library

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89

Parameter read only

Danfoss · VLT Micro Drive FC 51

What does 89 mean?

An attempt was made to write a value to a parameter that is configured as read-only. This typically occurs when trying to change system information, diagnostic values, or parameters that can only be modified internally by the drive, protecting critical settings.

Common Causes

  • Attempting to modify a system information parameter (e.g., drive serial number, firmware version in Parameter 15-05) which is inherently read-only.
  • Parameter is a diagnostic output value (e.g., motor current, output frequency in Parameter 16-10) which reflects real-time status and cannot be set.
  • Parameter access level (e.g., Parameter 16-00, 'Access code') is not set high enough to allow modification of protected parameters.
  • Parameter is part of an active process (e.g., autotuning via Parameter 8-00) and becomes read-only during that operation.
  • Control mode (e.g., Parameter 1-00) prevents writing to certain motion-related parameters while active.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the parameter number and check its attributes in the drive's programming manual to confirm if it is indeed read-only.

  2. 2

    Adjust the access level (e.g., set Parameter 16-00 to '3 - Advanced' or '4 - Expert') to enable writing to protected parameters.

  3. 3

    Ensure the drive is in a stopped state (output frequency at 0 Hz) before attempting to modify parameters related to motor control.

  4. 4

    Check if any special functions (e.g., Parameter 8-00, 'Auto-tune') are active and causing the parameter to be temporarily read-only.

  5. 5

    If attempting to modify a diagnostic value, understand that these are outputs and cannot be directly set; interpret them for troubleshooting.

Browse all codes in this manual (51)
Verified technical data. Last updated: April 2026

Related Faults

00Parameter number does not exist (Register 0007)01No write access to the parameter (Register 0007)02Data value exceeds parameter limits (Register 0007)
Source: Danfoss VLT Micro Drive FC 51
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