231-E008

SRG speed too high

Heidenhain · TNC CNC Controllers

What does 231-E008 mean?

This error indicates that the Safe Reduced Rotational Velocity (SRG) limit has been exceeded, or that the Heidenhain TNC CNC Controller failed to achieve a standstill during the Safe Controlled Stop (SBH) operating mode. This is a critical safety violation, as the machine is operating at an unsafe speed or has not stopped as commanded by a safety function, posing a risk of injury or damage.

Common Causes

  • The actual motor speed has exceeded the configured Safe Reduced Rotational Velocity (SRG) threshold.
  • The drive or motor failed to achieve standstill within the specified time during an active Safe Controlled Stop (SBH) command.
  • Malfunction in the speed monitoring system or the motor encoder feedback, leading to incorrect speed detection.
  • Incorrect parameterization of the SRG or SBH safety functions within the controller or safety module.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the actual motor speed using diagnostic tools on the Heidenhain TNC CNC Controller and compare it against the configured SRG limit parameter in the safety controller.

  2. 2

    Check the functionality of the motor encoder and its wiring for any damage, loose connections, or signal interference that could lead to inaccurate speed feedback.

  3. 3

    Review the parameters related to Safe Reduced Rotational Velocity (SRG) and Safe Controlled Stop (SBH) in the CNC controller and safety module; ensure they are correctly configured according to the machine's design and safety requirements.

  4. 4

    Perform a controlled test of the SBH function, monitoring the motor's deceleration and verifying that it reaches standstill within the specified time.

  5. 5

    If the issue persists after verifying parameters and feedback, consult a Heidenhain service agency for further diagnostics on the safety module or drive system.

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Verified technical data. Last updated: March 2026

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Source: Heidenhain TNC CNC Controllers