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ErrorLib — Industrial Fault Code Library

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08440000 hex

Overspeed Error

Omron · NJ/NX-series Machine Automation Controller

What does 08440000 hex mean?

The encoder detected the overspeed. This means the motor rotated at a speed exceeding its operational limits, which can lead to mechanical stress or system instability.

Common Causes

  • The motor was rotated by external forces
  • Encoder failure and false detection

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify maximum speed settings, scaling factors, and acceleration/deceleration parameters within the Omron NJ/NX controller and the connected servo drive.

  2. 2

    Inspect all encoder cabling and connections between the motor, servo drive, and Omron NJ/NX controller for physical damage, proper shielding, and secure termination.

  3. 3

    Monitor the actual motor speed feedback from the encoder and the commanded speed signal via the Omron NJ/NX diagnostic interface to identify any discrepancies or erratic behavior.

  4. 4

    Inspect the mechanical load and coupling connected to the motor for signs of binding, reduced resistance, or external forces that could contribute to uncontrolled acceleration.

Browse all codes in this manual (96)
Verified technical data. Last updated: April 2026

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04A10000Non-volatile Memory Hardware Error04A10000 hexNon-volatile Memory Hardware Error04AC0000 hexOvercurrent
Source: Omron NJ/NX-series Machine Automation Controller
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