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ErrorLib — Industrial Fault Code Library

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10021

Hall signals lost or incorrect

ABB · ACS850 Standard Program Firmware

What does 10021 mean?

This error occurs when a feedback type of 'halls only' or 'Encoder + Halls' is used, and the drive detects an illegal Hall sensor state (0 or 7). This typically points to a faulty encoder, especially if it includes simulated hall signals, or issues with its wiring. Unresolved, this prevents accurate motor commutation and control.

Common Causes

  • One or more Hall effect sensor signals (H1, H2, H3) are missing or stuck at a constant state (high or low).
  • Incorrect wiring or reversed polarity of Hall sensor power supply (+5V, 0V) or signal lines.
  • Physical damage or misalignment of the Hall sensors within the motor assembly.
  • Interference or electrical noise on the Hall sensor feedback lines causing intermittent incorrect states.
  • Incorrect feedback type selection in parameter P2-01 (Feedback device type) when Hall sensors are present.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the voltage levels of Hall sensor signals (H1, H2, H3) at the drive's feedback connector (e.g., X4 pins) while slowly rotating the motor shaft by hand. Verify expected phase sequence.

  2. 2

    Check the +5V Hall sensor supply voltage at the drive's feedback connector (e.g., X4/1) against 0V (e.g., X4/2) to ensure it is stable and within specification (e.g., 4.75V to 5.25V).

  3. 3

    Inspect Hall sensor cable shielding and grounding for integrity; ensure proper termination at the drive's protective ground (PE) terminal.

  4. 4

    Verify that parameter P2-01 (Feedback device type) is correctly configured for 'Halls Only' or 'Encoder + Halls' as per the motor's specification.

  5. 5

    Perform an independent continuity test on each Hall sensor signal wire from the motor connector to the drive connector.

Browse all codes in this manual (57)
Verified technical data. Last updated: April 2026

Related Faults

-Initialization error (Memory Unit / Recovery Mode)10019Motor temperature trip10020Phase search failure
Source: ABB ACS850 Standard Program Firmware
View Official PDFSearch more codes in this manual