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ErrorLib — Industrial Fault Code Library

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231-A004

Short circuit on 24 V of the T.BRK.B signal

Heidenhain · TNC CNC Controllers

What does 231-A004 mean?

This error signifies a short circuit on the +24 V line of the T.BRK.B signal, detected during a braking control test. Specifically, a +24 V signal level is present at the -T.BRK.B input of the SPL module when 0 V is expected, indicating an issue with the brake control circuit.

Common Causes

  • Error during braking control test.
  • Signal level is +24 V at input -T.BRK.B of the SPL module, although 0 V is expected due to the control.
  • External wiring of the brakes or T.BRK signal is faulty (e.g., short to +24 V).
  • Brake control relay is defective or stuck.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the external wiring of the brakes and the T.BRK signal for any damage, short circuits, or loose connections.

  2. 2

    Measure the voltage at the -T.BRK.B input of the SPL module when 0 V is commanded by the control; it should read 0 V.

  3. 3

    Check the functionality of the relay responsible for brake control. Verify its coil and contact states.

  4. 4

    Perform continuity tests on the T.BRK.B signal line to ensure no unintentional connection to +24 V.

Browse all codes in this manual (47)
Verified technical data. Last updated: April 2026

Related Faults

231-A001Cancelation of brake-test call monitoring231-A002Cancelation of brake-line-test call monitoring231-A003SPLC commissioning mode active
Source: Heidenhain TNC CNC Controllers
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