Heidenhain codes
HeidenhainSystemIntermediate30-120 minutes

231-8320

HEIDENHAIN 231-8320 - 8320 PIC: Actual value does not equal the nominal value

8320 PIC: Actual value does not equal the nominal value

This TNC 640 error indicates an internal control fault. The issue relates to Possible cause: The measurement range of current of the inve.

Root Cause Summary

Alarm 231-8320 occurs when there's a mismatch between the configured PIC (Power Interface Controller) current measurement range setting and the actual hardware state. This typically happens after CC controller replacement, configuration changes, or when the PIC microcontroller cannot be properly accessed or switched to the required measurement range.

Safety

  • Refer to Heidenhain service manual
  • Ensure qualified technician performs repairs

Causes and Fixes

  1. 1

    Access Power Module Configuration

    Navigate to MOD function → Machine Parameters → Power section to verify power module table column S values match installed hardware.

    Document original settings before any CC controller replacement

  2. 2

    Check PIC Communication

    Verify PIC microcontroller communication by checking inverter status in the servo diagnostic screens under Test Run mode.

    Ensure machine is in safe state before accessing servo diagnostics

  3. 3

    Reconfigure Current Range

    Set the correct current measurement range in the power module configuration to match the new CC controller specifications.

    Cross-reference CC controller part number with Heidenhain power module compatibility charts

  4. 4

    Perform System Restart

    Execute a complete TNC restart to reinitialize PIC communication and verify configuration changes take effect.

DIY Feasiblehigh confidence

Call a technician if:

  • ·PIC hardware failure confirmed
  • ·Multiple inverter modules affected
  • ·Configuration restoration unsuccessful after multiple attempts

Prevention

  • Always backup machine parameters before CC controller replacement
  • Document power module specifications during initial installation
  • Regularly verify motEncCheckOff parameter settings during maintenance

Common Mistakes

  • Forgetting to restart TNC after parameter changes
  • Mixing power module configurations between different machine types
  • Not verifying PIC communication before declaring hardware failure

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Always verify with your machine manual or a certified technician before performing service procedures.